Runtime Environment

  • Device Emulation (Nexus 5X): Disabled

  • Network Throttling (150ms RTT, 1.6Mbps down, 0.7Mbps up): Disabled

  • CPU Throttling (5x slowdown): Disabled

Progressive Web App

These audits validate the aspects of a Progressive Web App. They are a subset of the PWA Checklist.

91 / 100

App can load on offline/flaky connections

Ensuring your web app can respond when the network connection is unavailable or flaky is critical to providing your users a good experience. This is achieved through use of a Service Worker.

  • Registers a Service Worker The service worker is the technology that enables your app to use many Progressive Web App features, such as offline, add to homescreen, and push notifications. Learn more.

    Pass
  • Responds with a 200 when offline If you're building a Progressive Web App, consider using a service worker so that your app can work offline. Learn more.

    Pass

Page load performance is fast

Users notice if sites and apps don't perform well. These top-level metrics capture the most important perceived performance concerns.

  • First meaningful paint: 1903.6ms (target: 1,600ms) First meaningful paint measures when the primary content of a page is visible. Learn more.

    93
  • Perceptual Speed Index: 4242 (target: 1,250) Speed Index shows how quickly the contents of a page are visibly populated. Learn more.

    64
    • First Visual Change: 2006ms
    • Last Visual Change: 7648ms
  • Estimated Input Latency: 68.8ms (target: 50ms) The score above is an estimate of how long your app takes to respond to user input, in milliseconds. There is a 90% probability that a user encounters this amount of latency, or less. 10% of the time a user can expect additional latency. If your score is higher than Lighthouse's target score, users may perceive your app as laggy. Learn more.

    81
  • Time To Interactive (alpha): 4051.6ms (target: 5,000ms) Time to Interactive identifies the time at which your app appears to be ready enough to interact with. Learn more.

    64

Site is progressively enhanced

Progressive enhancement means that everyone can access the basic content and functionality of a page in any browser, and those without certain browser features may receive a reduced but still functional experience.

  • Contains some content when JavaScript is not available Your app should display some content when JavaScript is disabled, even if it's just a warning to the user that JavaScript is required to use the app. Learn more.

    Pass

Network connection is secure

Security is an important part of the web for both developers and users. Moving forward, Transport Layer Security (TLS) support will be required for many APIs.

  • Uses HTTPS All sites should be protected with HTTPS, even ones that don't handle sensitive data. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs. Learn more.

    Pass
  • Redirects HTTP traffic to HTTPS If you've already set up HTTPS, make sure that you redirect all HTTP traffic to HTTPS. Learn more.

    Fail

User can be prompted to Add to Homescreen

While users can manually add your site to their homescreen in the browser menu, the prompt (aka app install banner) will proactively prompt the user to install the app if the below requirements are met and the user has visited your site at least twice (with at least five minutes between visits).

  • Registers a Service Worker The service worker is the technology that enables your app to use many Progressive Web App features, such as offline, add to homescreen, and push notifications. Learn more.

    Pass
  • Manifest exists The web app manifest is the technology that enables users to add your web app to their homescreen. Learn more.

    Pass
  • Manifest contains start_url Add a start_url to instruct the browser to launch a specific URL whenever your app is launched from a homescreen. Learn more.

    Pass
  • Manifest contains icons at least 144px: found sizes: 152x152, 144x144, 192x192, 384x384

    Pass
  • Manifest contains short_name The short_name property is a requirement for Add To Homescreen. Learn more.

    Pass

Installed web app will launch with custom splash screen

A default splash screen will be constructed, but meeting these requirements guarantee a high-quality and customizable splash screen the user sees between tapping the home screen icon and your app's first paint.

  • Manifest exists The web app manifest is the technology that enables users to add your web app to their homescreen. Learn more.

    Pass
  • Manifest contains name The name property identifies your app and is required. Learn more.

    Pass
  • Manifest contains background_color When your app launches from a user's homescreen, the browser uses background_color to paint the background of the browser while your app loads for a smooth transition experience. Learn more.

    Pass
  • Manifest contains theme_color Add a theme_color to set the color of the browser's address bar. Learn more.

    Pass
  • Manifest contains icons at least 192px: found sizes: 192x192, 384x384 A 192px icon ensures that your app's icon displays well on the homescreens of the largest mobile devices. Learn more.

    Pass

Address bar matches brand colors

The browser address bar can be themed to match your site. A theme-color meta tag will upgrade the address bar when a user browses the site, and the manifest theme-color will apply the same theme site-wide once it's been added to homescreen.

  • Manifest exists The web app manifest is the technology that enables users to add your web app to their homescreen. Learn more.

    Pass
  • Has a <meta name="theme-color"> tag: #222222

    Pass
  • Manifest contains theme_color Add a theme_color to set the color of the browser's address bar. Learn more.

    Pass

Design is mobile-friendly

Users increasingly experience your app on mobile devices, so it's important to ensure that the experience can adapt to smaller screens.

  • Has a <meta name="viewport"> tag with width or initial-scale Add a viewport meta tag to optimize your app for mobile screens. Learn more.

    Pass
  • Content is sized correctly for the viewport If the width of your app's content doesn't match the width of the viewport, your app might not be optimized for mobile screens. Learn more.

    Pass

Best Practices

We've compiled some recommendations for modernizing your web app and avoiding performance pitfalls. These audits do not affect your score but are worth a look.

Using modern offline features

Using modern protocols

  • Uses HTTPS All sites should be protected with HTTPS, even ones that don't handle sensitive data. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs. Learn more.

    Pass
  • Uses HTTP/2 for its own resources HTTP/2 offers many benefits over HTTP/1.1, including binary headers, multiplexing, and server push. Learn more.

    Pass

Using modern CSS features

  • Avoids old CSS flexbox The 2009 spec of Flexbox is deprecated and is 2.3x slower than the latest spec. Learn more.

    Pass

Using modern JavaScript features

  • Uses passive listeners to improve scrolling performance Consider marking your touch and wheel event listeners as passive to improve your page's scroll performance. Learn more.

    Pass
  • Avoids Mutation Events in its own scripts Mutation Events are deprecated and harm performance. Consider using Mutation Observers instead. Learn more.

    Pass

Avoiding APIs that harm the user experience

  • Avoids document.write() For users on slow connections, external scripts dynamically injected via document.write() can delay page load by tens of seconds. Learn more.

    Pass
  • Opens external anchors using rel="noopener" Open new tabs using rel="noopener" to improve performance and prevent security vulnerabilities. Learn more.

    Pass
  • Avoids requesting the geolocation permission on page load Users are mistrustful of or confused by sites that request their location without context. Consider tying the request to user gestures instead. Learn more.

    Pass
  • Avoids requesting the notification permission on page load Users are mistrustful of or confused by sites that request to send notifications without context. Consider tying the request to user gestures instead. Learn more.

    Pass

Avoiding deprecated APIs and browser interventions

  • Avoids deprecated APIs: 1 warning found Deprecated APIs will eventually be removed from the browser. Learn more.

    Fail
    URLs
    • https://s-usc1c-nss-137.firebaseio.com/.lp?dframe=t&id=106465&pw=9K9EEyIUTY&ns=hacker-news (line: 4)
      Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check https://xhr.spec.whatwg.org/.

Accessibility

  • Element aria-* attributes are allowed for this role Each ARIA role supports a specific subset of aria-* attributes. Mismatching these invalidates the aria-* attributes. Learn more.

    Pass
  • Elements with ARIA roles have the required aria-* attributes Some ARIA roles have required attributes that describe the state of the element to screen readers. Learn more.

    Pass
  • Element aria-* attributes are valid and not misspelled or non-existent. Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid names. Learn more.

    Pass
  • Element aria-* attributes have valid values Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid values. Learn more.

    Pass
  • Background and foreground colors have a sufficient contrast ratio Low-contrast text is difficult or impossible for many users to read. Learn more.

    Pass
  • Every image element has an alt attribute Screen reader users rely on alt text to provide descriptions of images. It's also used as fallback content when an image fails to load. Learn more.

    Pass
  • Every form element has a label Labels ensure that form controls are announced properly by assistive technologies, like screen readers. Learn more.

    Pass
  • No element has a tabindex attribute greater than 0 A value greater than 0 implies an explicit navigation ordering. Although technically valid, this often creates frustrating experiences for users who rely on assistive technologies. Learn more.

    Pass

Other

  • Manifest's short_name won't be truncated when displayed on homescreen Make your app's short_name less than 12 characters to ensure that it's not truncated on homescreens. Learn more.

    Pass
  • Manifest's display property is set: standalone Set the display property to specify how your app launches from the homescreen. Learn more.

    Pass

Performance

These encapsulate your app's performance.

  • Unoptimized images Images should be optimized to save network bytes. The following images could have smaller file sizes when compressed with WebP or JPEG at 80 quality. Learn more about image optimization.

    Pass
  • Oversized Images Image sizes served should be based on the device display size to save network bytes. Learn more about responsive images and client hints.

    Pass
  • Critical Request Chains: 6 The Critical Request Chains below show you what resources are required for first render of this page. Improve page load by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources. Learn more.

    Fail
    • Longest chain: 6,747.3ms over 1 requests, totalling 2.95KB
    • View critical network waterfall
      Initial navigation
      / (react-hn.appspot.com)
      …css/style.css (react-hn.appspot.com) - 1,726.3ms, 6.62KB
      …img/logo.png (react-hn.appspot.com) - 1,866ms, 5.05KB
      /manifest.d41d8cd9.js (react-hn.appspot.com) - 2,115.3ms, 6.18KB
      /core.js (react-hn.appspot.com) - 2,124ms, 5.35KB
      /app.c8553140.js (react-hn.appspot.com) - 2,222.7ms, 14.5KB
      /vendor.4b459b7e.js (react-hn.appspot.com) - 3,139.7ms, 116.5KB
      …img/apple-touch-icon-144x144.png (react-hn.appspot.com) - 5,945ms, 2.96KB
      …img/android-chrome-192x192.png (react-hn.appspot.com) - 6,077.1ms, 3.74KB
      /manifest.json (react-hn.appspot.com) - 6,183.1ms, 0.52KB
      …img/android-chrome-144x144.png (react-hn.appspot.com) - 6,747.3ms, 2.95KB
  • Render-blocking Stylesheets: 1 resource delayed first paint by 28ms Link elements are blocking the first paint of your page. Consider inlining critical links and deferring non-critical ones. Learn more.

    Fail
    View details
    URL Size (KB) Delayed Paint By (ms)
    …css/style.css 0 KB 28ms
  • Render-blocking scripts Script elements are blocking the first paint of your page. Consider inlining critical scripts and deferring non-critical ones. Learn more.

    Pass
  • Avoids enormous network payloads: Total size was 154 KB (target: 1,600 KB) Network transfer size costs users real dollars and is highly correlated with long load times. Try to find ways to reduce the size of required files.

    100
    View details
    URL Total Size Transfer Time
    /vendor.4b459b7e.js 112 KB 820ms
    /analytics.js 12 KB 90ms
    /app.c8553140.js 10 KB 70ms
    / 5 KB 30ms
    …img/android-chrome-192x192.png 4 KB 30ms
    …img/apple-touch-icon-144x144.png 3 KB 20ms
    …img/android-chrome-144x144.png 3 KB 20ms
    …css/style.css 2 KB 10ms
    /manifest.d41d8cd9.js 2 KB 10ms
    /core.js 1 KB 0ms
  • Avoids an excessive DOM size: 358 nodes (target: 1,500 nodes) Browser engineers recommend pages contain fewer than ~1,500 DOM nodes. The sweet spot is a tree depth < 32 elements and fewer than 60 children/parent element. A large DOM can increase memory, cause longer style calculations, and produce costly layout reflows. Learn more.

    100
    More information
    Total DOM Nodes
    358
    target: < 1,500 nodes
    DOM Depth
    12
    target: < 32
    Maximum Children
    30
    target: < 60 nodes
  • User Timing marks and measures: 0 Consider instrumenting your app with the User Timing API to create custom, real-world measurements of key user experiences. Learn more.

    Pass

Fancier stuff

A list of newer features that you could be using in your app. These audits do not affect your score and are just suggestions.

New JavaScript features

  • Avoids Date.now() in its own scripts Consider using performance.now() from the User Timing API instead. It provides high-precision timestamps, independent of the system clock. Learn more.

    Fail
    View details
    URL Line/Col Eval'd?
    https://react-hn.appspot.com/vendor.4b459b7e.js 7:19948
    https://react-hn.appspot.com/vendor.4b459b7e.js 7:19071
  • Avoids console.time() in its own scripts Consider using performance.mark() and performance.measure() from the User Timing API instead. They provide high-precision timestamps, independent of the system clock, and are integrated in the Chrome DevTools Timeline. Learn more.

    Pass
{ "lighthouseVersion": "1.6.5", "generatedTime": "2017-05-11T05:19:00.380Z", "initialUrl": "https://react-hn.appspot.com/", "url": "https://react-hn.appspot.com/", "audits": { "is-on-https": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "urllist", "value": [] }, "name": "is-on-https", "category": "Security", "description": "Uses HTTPS", "helpText": "All sites should be protected with HTTPS, even ones that don't handle sensitive data. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/https)." }, "redirects-http": { "score": false, "displayValue": "", "rawValue": false, "name": "redirects-http", "category": "Security", "description": "Redirects HTTP traffic to HTTPS", "helpText": "If you've already set up HTTPS, make sure that you redirect all HTTP traffic to HTTPS. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/http-redirects-to-https)." }, "service-worker": { "score": true, "displayValue": "", "rawValue": true, "name": "service-worker", "category": "Offline", "description": "Registers a Service Worker", "helpText": "The service worker is the technology that enables your app to use many Progressive Web App features, such as offline, add to homescreen, and push notifications. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/registered-service-worker)." }, "works-offline": { "score": true, "displayValue": "", "rawValue": true, "name": "works-offline", "category": "Offline", "description": "Responds with a 200 when offline", "helpText": "If you're building a Progressive Web App, consider using a service worker so that your app can work offline. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/http-200-when-offline)." }, "viewport": { "score": true, "displayValue": "", "rawValue": true, "debugString": "", "name": "viewport", "category": "Mobile Friendly", "description": "Has a `<meta name=\"viewport\">` tag with `width` or `initial-scale`", "helpText": "Add a viewport meta tag to optimize your app for mobile screens. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/has-viewport-meta-tag)." }, "manifest-display": { "score": true, "displayValue": "standalone", "rawValue": true, "name": "manifest-display", "category": "Manifest", "description": "Manifest's `display` property is set", "helpText": "Set the `display` property to specify how your app launches from the homescreen. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-has-display-set)." }, "without-javascript": { "score": true, "displayValue": "", "rawValue": true, "name": "without-javascript", "category": "JavaScript", "description": "Contains some content when JavaScript is not available", "helpText": "Your app should display some content when JavaScript is disabled, even if it's just a warning to the user that JavaScript is required to use the app. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/no-js)." }, "first-meaningful-paint": { "score": 93, "displayValue": "1903.6ms", "rawValue": 1903.6, "optimalValue": "1,600ms", "extendedInfo": { "value": { "timestamps": { "navStart": 5987641858569, "fCP": 5987643762143, "fMP": 5987643762181 }, "timings": { "navStart": 0, "fCP": 1903.574, "fMP": 1903.612 } }, "formatter": "null" }, "name": "first-meaningful-paint", "category": "Performance", "description": "First meaningful paint", "helpText": "First meaningful paint measures when the primary content of a page is visible. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/first-meaningful-paint)." }, "speed-index-metric": { "score": 64, "displayValue": "4242", "rawValue": 4242, "optimalValue": "1,250", "extendedInfo": { "formatter": "speedline", "value": { "timings": { "firstVisualChange": 2006, "visuallyComplete": 7648, "speedIndex": 2540.2272597694396, "perceptualSpeedIndex": 4241.957836370474 }, "timestamps": { "firstVisualChange": 5987643832937, "visuallyComplete": 5987649474937, "speedIndex": 5987644367164.26, "perceptualSpeedIndex": 5987646068894.836 }, "frames": [ { "timestamp": 5987641826.937, "progress": 47.98721851076965 }, { "timestamp": 5987643833.684, "progress": 0 }, { "timestamp": 5987643886.949, "progress": 0.10727798594122007 }, { "timestamp": 5987645725.913, "progress": 0.10727798594122007 }, { "timestamp": 5987645741.09, "progress": 0.10727798594122007 }, { "timestamp": 5987645910.182, "progress": 94.22555355364392 }, { "timestamp": 5987646000.386, "progress": 93.21843471574395 }, { "timestamp": 5987646134.825, "progress": 92.56412270729415 }, { "timestamp": 5987646198.926, "progress": 93.46887239213888 }, { "timestamp": 5987646257.77, "progress": 93.06349622048947 }, { "timestamp": 5987646319.492, "progress": 92.85146528355475 }, { "timestamp": 5987646420.551, "progress": 93.64463254959362 }, { "timestamp": 5987646502.884, "progress": 94.42447288826193 }, { "timestamp": 5987646669.898, "progress": 95.44426724912647 }, { "timestamp": 5987646845.207, "progress": 95.77480886510479 }, { "timestamp": 5987646936.984, "progress": 95.34270408602616 }, { "timestamp": 5987646974.703, "progress": 95.34270408602616 }, { "timestamp": 5987647103.923, "progress": 95.20932319786785 }, { "timestamp": 5987647167.411, "progress": 95.10233986301505 }, { "timestamp": 5987647228.743, "progress": 94.71061164566818 }, { "timestamp": 5987647291.399, "progress": 94.22331727951135 }, { "timestamp": 5987647354.366, "progress": 93.71725411688175 }, { "timestamp": 5987647421.922, "progress": 92.99085268800711 }, { "timestamp": 5987647500.876, "progress": 92.41096867850513 }, { "timestamp": 5987647577.113, "progress": 92.92347073307434 }, { "timestamp": 5987647658.579, "progress": 93.06321394854868 }, { "timestamp": 5987647720.306, "progress": 92.85167408858212 }, { "timestamp": 5987647824.149, "progress": 93.70233887455166 }, { "timestamp": 5987647929.067, "progress": 95.67474016800402 }, { "timestamp": 5987648037.238, "progress": 99.31573778946465 }, { "timestamp": 5987648175.362, "progress": 98.88184299876657 }, { "timestamp": 5987648222.791, "progress": 98.55170313872325 }, { "timestamp": 5987648294.437, "progress": 98.45589084854689 }, { "timestamp": 5987648398.34, "progress": 98.44805989179714 }, { "timestamp": 5987648458.672, "progress": 98.44805989179714 }, { "timestamp": 5987648560.845, "progress": 98.31467900363883 }, { "timestamp": 5987648608.905, "progress": 97.8392321567253 }, { "timestamp": 5987648683.639, "progress": 97.33090935941489 }, { "timestamp": 5987648739.325, "progress": 96.88088051936059 }, { "timestamp": 5987648806.713, "progress": 96.32537891209041 }, { "timestamp": 5987648884.169, "progress": 95.51128794025958 }, { "timestamp": 5987648957.862, "progress": 95.75552430951551 }, { "timestamp": 5987649042.866, "progress": 96.3538014895469 }, { "timestamp": 5987649110.439, "progress": 95.93234987259468 }, { "timestamp": 5987649191.179, "progress": 96.47197740281563 }, { "timestamp": 5987649258.077, "progress": 97.22630292317827 }, { "timestamp": 5987649322.852, "progress": 97.75642470542016 }, { "timestamp": 5987649393.601, "progress": 98.73658054866854 }, { "timestamp": 5987649475.521, "progress": 100.00000000000001 } ] } }, "name": "speed-index-metric", "category": "Performance", "description": "Perceptual Speed Index", "helpText": "Speed Index shows how quickly the contents of a page are visibly populated. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/speed-index)." }, "estimated-input-latency": { "score": 81, "displayValue": "68.8ms", "rawValue": 68.8, "optimalValue": "50ms", "extendedInfo": { "value": [ { "percentile": 0.5, "time": 16 }, { "percentile": 0.75, "time": 16.34444855476577 }, { "percentile": 0.9, "time": 68.82830000591343 }, { "percentile": 0.99, "time": 449.40702000236706 }, { "percentile": 1, "time": 508.3710000000019 } ], "formatter": "null" }, "name": "estimated-input-latency", "category": "Performance", "description": "Estimated Input Latency", "helpText": "The score above is an estimate of how long your app takes to respond to user input, in milliseconds. There is a 90% probability that a user encounters this amount of latency, or less. 10% of the time a user can expect additional latency. If your score is higher than Lighthouse's target score, users may perceive your app as laggy. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/estimated-input-latency)." }, "time-to-interactive": { "score": 64, "displayValue": "4051.6ms", "rawValue": 4051.6, "optimalValue": "5,000ms", "extendedInfo": { "value": { "timings": { "fMP": 1903.6, "visuallyReady": 4051.613, "timeToInteractive": 4051.613 }, "timestamps": { "fMP": 5987643762181, "visuallyReady": 5987645910182, "timeToInteractive": 5987645910182 }, "expectedLatencyAtTTI": 20.457, "foundLatencies": [ { "estLatency": 20.456749952316258, "startTime": "4051.6" } ] }, "formatter": "null" }, "name": "time-to-interactive", "category": "Performance", "description": "Time To Interactive (alpha)", "helpText": "Time to Interactive identifies the time at which your app appears to be ready enough to interact with. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/time-to-interactive)." }, "user-timings": { "score": true, "displayValue": "0", "rawValue": true, "extendedInfo": { "formatter": "userTimings", "value": [] }, "informative": true, "name": "user-timings", "category": "Performance", "description": "User Timing marks and measures", "helpText": "Consider instrumenting your app with the User Timing API to create custom, real-world measurements of key user experiences. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/user-timing)." }, "critical-request-chains": { "score": false, "displayValue": "6", "rawValue": false, "optimalValue": 0, "extendedInfo": { "formatter": "criticalRequestChains", "value": { "15692.1": { "request": { "url": "https://react-hn.appspot.com/", "startTime": 5987641.90899, "endTime": 5987643.206606, "responseReceivedTime": 5987643.165806, "transferSize": 4794 }, "children": { "15692.2": { "request": { "url": "https://react-hn.appspot.com/css/style.css", "startTime": 5987643.232062, "endTime": 5987643.635266, "responseReceivedTime": 5987643.612755, "transferSize": 1987 }, "children": {} }, "15692.3": { "request": { "url": "https://react-hn.appspot.com/img/logo.png", "startTime": 5987643.234548, "endTime": 5987643.77499, "responseReceivedTime": 5987643.769936, "transferSize": 380 }, "children": {} }, "15692.6": { "request": { "url": "https://react-hn.appspot.com/manifest.d41d8cd9.js", "startTime": 5987643.638648, "endTime": 5987644.024285, "responseReceivedTime": 5987644.017136, "transferSize": 1536 }, "children": {} }, "15692.5": { "request": { "url": "https://react-hn.appspot.com/core.js", "startTime": 5987643.637573, "endTime": 5987644.033014, "responseReceivedTime": 5987644.026095, "transferSize": 684 }, "children": {} }, "15692.8": { "request": { "url": "https://react-hn.appspot.com/app.c8553140.js", "startTime": 5987643.64225, "endTime": 5987644.131681, "responseReceivedTime": 5987644.035999, "transferSize": 10055 }, "children": {} }, "15692.7": { "request": { "url": "https://react-hn.appspot.com/vendor.4b459b7e.js", "startTime": 5987643.641492, "endTime": 5987645.048714, "responseReceivedTime": 5987644.135171, "transferSize": 114502 }, "children": {} } } }, "15692.63": { "request": { "url": "https://react-hn.appspot.com/img/apple-touch-icon-144x144.png", "startTime": 5987646.945635, "endTime": 5987647.853953, "responseReceivedTime": 5987647.834083, "transferSize": 3033 }, "children": {} }, "15692.62": { "request": { "url": "https://react-hn.appspot.com/img/android-chrome-192x192.png", "startTime": 5987646.944652, "endTime": 5987647.986053, "responseReceivedTime": 5987647.98236, "transferSize": 3833 }, "children": {} }, "15692.61": { "request": { "url": "https://react-hn.appspot.com/manifest.json", "startTime": 5987646.926169, "endTime": 5987648.092081, "responseReceivedTime": 5987648.089057, "transferSize": 533 }, "children": {} }, "15692.65": { "request": { "url": "https://react-hn.appspot.com/img/android-chrome-144x144.png", "startTime": 5987648.109951, "endTime": 5987648.656293, "responseReceivedTime": 5987648.65065, "transferSize": 3019 }, "children": {} } } }, "informative": true, "name": "critical-request-chains", "category": "Performance", "description": "Critical Request Chains", "helpText": "The Critical Request Chains below show you what resources are required for first render of this page. Improve page load by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/critical-request-chains)." }, "manifest-exists": { "score": true, "displayValue": "", "rawValue": true, "name": "manifest-exists", "category": "Manifest", "description": "Manifest exists", "helpText": "The web app manifest is the technology that enables users to add your web app to their homescreen. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-exists)." }, "manifest-background-color": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "value": "#4CC1FC", "formatter": "null" }, "name": "manifest-background-color", "category": "Manifest", "description": "Manifest contains `background_color`", "helpText": "When your app launches from a user's homescreen, the browser uses `background_color` to paint the background of the browser while your app loads for a smooth transition experience. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-contains-background_color)." }, "manifest-theme-color": { "score": true, "displayValue": "", "rawValue": true, "name": "manifest-theme-color", "category": "Manifest", "description": "Manifest contains `theme_color`", "helpText": "Add a `theme_color` to set the color of the browser's address bar. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-contains-theme_color)." }, "manifest-icons-min-192": { "score": true, "displayValue": "found sizes: 192x192, 384x384", "rawValue": true, "name": "manifest-icons-min-192", "category": "Manifest", "description": "Manifest contains icons at least 192px", "helpText": "A 192px icon ensures that your app's icon displays well on the homescreens of the largest mobile devices. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-contains-192px-icon)." }, "manifest-icons-min-144": { "score": true, "displayValue": "found sizes: 152x152, 144x144, 192x192, 384x384", "rawValue": true, "name": "manifest-icons-min-144", "category": "Manifest", "description": "Manifest contains icons at least 144px" }, "manifest-name": { "score": true, "displayValue": "", "rawValue": true, "name": "manifest-name", "category": "Manifest", "description": "Manifest contains `name`", "helpText": "The `name` property identifies your app and is required. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-contains-name)." }, "manifest-short-name": { "score": true, "displayValue": "", "rawValue": true, "name": "manifest-short-name", "category": "Manifest", "description": "Manifest contains `short_name`", "helpText": "The `short_name` property is a requirement for Add To Homescreen. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-contains-short_name)." }, "manifest-short-name-length": { "score": true, "displayValue": "", "rawValue": true, "name": "manifest-short-name-length", "category": "Manifest", "description": "Manifest's `short_name` won't be truncated when displayed on homescreen", "helpText": "Make your app's `short_name` less than 12 characters to ensure that it's not truncated on homescreens. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-short_name-is-not-truncated)." }, "manifest-start-url": { "score": true, "displayValue": "", "rawValue": true, "name": "manifest-start-url", "category": "Manifest", "description": "Manifest contains `start_url`", "helpText": "Add a `start_url` to instruct the browser to launch a specific URL whenever your app is launched from a homescreen. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-contains-start_url)." }, "theme-color-meta": { "score": true, "displayValue": "#222222", "rawValue": true, "name": "theme-color-meta", "category": "HTML", "description": "Has a `<meta name=\"theme-color\">` tag" }, "content-width": { "score": true, "displayValue": "", "rawValue": true, "debugString": "", "name": "content-width", "category": "Mobile Friendly", "description": "Content is sized correctly for the viewport", "helpText": "If the width of your app's content doesn't match the width of the viewport, your app might not be optimized for mobile screens. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/content-sized-correctly-for-viewport)." }, "deprecations": { "score": false, "displayValue": "1 warning found", "rawValue": false, "extendedInfo": { "formatter": "urllist", "value": [ { "label": "line: 4", "url": "https://s-usc1c-nss-137.firebaseio.com/.lp?dframe=t&id=106465&pw=9K9EEyIUTY&ns=hacker-news", "code": "Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check https://xhr.spec.whatwg.org/.", "source": "deprecation", "level": "warning", "text": "Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check https://xhr.spec.whatwg.org/.", "timestamp": 1494479813073.25, "lineNumber": 4, "stackTrace": { "callFrames": [ { "functionName": "EnvSendPing", "scriptId": "82", "url": "https://s-usc1c-nss-137.firebaseio.com/.lp?dframe=t&id=106465&pw=9K9EEyIUTY&ns=hacker-news", "lineNumber": 4, "columnNumber": 4 }, { "functionName": "EnvDisconnect", "scriptId": "82", "url": "https://s-usc1c-nss-137.firebaseio.com/.lp?dframe=t&id=106465&pw=9K9EEyIUTY&ns=hacker-news", "lineNumber": 9, "columnNumber": 0 }, { "functionName": "X2NH.g.Tc", "scriptId": "62", "url": "https://react-hn.appspot.com/vendor.4b459b7e.js", "lineNumber": 3, "columnNumber": 16233 }, { "functionName": "X2NH.g.fb", "scriptId": "62", "url": "https://react-hn.appspot.com/vendor.4b459b7e.js", "lineNumber": 3, "columnNumber": 16383 }, { "functionName": "", "scriptId": "62", "url": "https://react-hn.appspot.com/vendor.4b459b7e.js", "lineNumber": 3, "columnNumber": 15178 }, { "functionName": "Sb", "scriptId": "62", "url": "https://react-hn.appspot.com/vendor.4b459b7e.js", "lineNumber": 1, "columnNumber": 8551 }, { "functionName": "", "scriptId": "62", "url": "https://react-hn.appspot.com/vendor.4b459b7e.js", "lineNumber": 3, "columnNumber": 15155 }, { "functionName": "pLPCommand", "scriptId": "73", "url": "https://s-usc1c-nss-137.firebaseio.com/.lp?start=t&ser=37615714&cb=1&v=5&ns=hacker-news", "lineNumber": 2, "columnNumber": 60 }, { "functionName": "", "scriptId": "86", "url": "https://s-usc1c-nss-137.firebaseio.com/.lp?id=106465&pw=9K9EEyIUTY&ser=16166152&ns=hacker-news&seg0=32&ts0=1&d0=eyJ0IjoiYyIsImQiOnsidCI6Im4iLCJkIjp7fX19", "lineNumber": 1, "columnNumber": 0 } ] } } ] }, "name": "deprecations", "category": "Deprecations", "description": "Avoids deprecated APIs", "helpText": "Deprecated APIs will eventually be removed from the browser. [Learn more](https://www.chromestatus.com/features#deprecated)." }, "aria-allowed-attr": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "aria-allowed-attr", "category": "Accessibility", "description": "Element aria-* attributes are allowed for this role", "helpText": "Each ARIA `role` supports a specific subset of `aria-*` attributes. Mismatching these invalidates the `aria-*` attributes. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/aria-allowed-attributes)." }, "aria-required-attr": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "aria-required-attr", "category": "Accessibility", "description": "Elements with ARIA roles have the required aria-* attributes", "helpText": "Some ARIA roles have required attributes that describe the state of the element to screen readers. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/required-aria-attributes)." }, "aria-valid-attr-value": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "aria-valid-attr-value", "category": "Accessibility", "description": "Element aria-* attributes have valid values", "helpText": "Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid values. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/valid-aria-values)." }, "aria-valid-attr": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "aria-valid-attr", "category": "Accessibility", "description": "Element aria-* attributes are valid and not misspelled or non-existent.", "helpText": "Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid names. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/valid-aria-attributes)." }, "color-contrast": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "color-contrast", "category": "Accessibility", "description": "Background and foreground colors have a sufficient contrast ratio", "helpText": "Low-contrast text is difficult or impossible for many users to read. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/contrast-ratio)." }, "image-alt": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "image-alt", "category": "Accessibility", "description": "Every image element has an alt attribute", "helpText": "Screen reader users rely on `alt` text to provide descriptions of images. It's also used as fallback content when an image fails to load. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/alt-attribute)." }, "label": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "label", "category": "Accessibility", "description": "Every form element has a label", "helpText": "Labels ensure that form controls are announced properly by assistive technologies, like screen readers. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/form-labels)." }, "tabindex": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "tabindex", "category": "Accessibility", "description": "No element has a `tabindex` attribute greater than 0", "helpText": "A value greater than 0 implies an explicit navigation ordering. Although technically valid, this often creates frustrating experiences for users who rely on assistive technologies. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/tabindex)." }, "total-byte-weight": { "score": 100, "displayValue": "Total size was 154 KB", "rawValue": 157486, "optimalValue": "1,600 KB", "extendedInfo": { "formatter": "table", "value": { "results": [ { "url": "/vendor.4b459b7e.js", "totalBytes": 114502, "totalKb": "112 KB", "totalMs": "820ms" }, { "url": "/analytics.js", "totalBytes": 12542, "totalKb": "12 KB", "totalMs": "90ms" }, { "url": "/app.c8553140.js", "totalBytes": 10055, "totalKb": "10 KB", "totalMs": "70ms" }, { "url": "/", "totalBytes": 4794, "totalKb": "5 KB", "totalMs": "30ms" }, { "url": "…img/android-chrome-192x192.png", "totalBytes": 3833, "totalKb": "4 KB", "totalMs": "30ms" }, { "url": "…img/apple-touch-icon-144x144.png", "totalBytes": 3033, "totalKb": "3 KB", "totalMs": "20ms" }, { "url": "…img/android-chrome-144x144.png", "totalBytes": 3019, "totalKb": "3 KB", "totalMs": "20ms" }, { "url": "…css/style.css", "totalBytes": 1987, "totalKb": "2 KB", "totalMs": "10ms" }, { "url": "/manifest.d41d8cd9.js", "totalBytes": 1536, "totalKb": "2 KB", "totalMs": "10ms" }, { "url": "/core.js", "totalBytes": 684, "totalKb": "1 KB", "totalMs": "0ms" } ], "tableHeadings": { "url": "URL", "totalKb": "Total Size", "totalMs": "Transfer Time" } } }, "informative": true, "name": "total-byte-weight", "category": "Network", "description": "Avoids enormous network payloads", "helpText": "Network transfer size [costs users real dollars](https://whatdoesmysitecost.com/) and is [highly correlated](http://httparchive.org/interesting.php#onLoad) with long load times. Try to find ways to reduce the size of required files." }, "uses-optimized-images": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "preview": "", "url": "URL", "totalKb": "Original", "webpSavings": "WebP Savings", "jpegSavings": "JPEG Savings" } } }, "informative": true, "name": "uses-optimized-images", "category": "Images", "description": "Unoptimized images", "helpText": "Images should be optimized to save network bytes. The following images could have smaller file sizes when compressed with [WebP](https://developers.google.com/speed/webp/) or JPEG at 80 quality. [Learn more about image optimization](https://developers.google.com/web/fundamentals/performance/optimizing-content-efficiency/image-optimization)." }, "uses-responsive-images": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "preview": "", "url": "URL", "totalKb": "Original", "potentialSavings": "Potential Savings" } } }, "informative": true, "name": "uses-responsive-images", "category": "Images", "description": "Oversized Images", "helpText": "Image sizes served should be based on the device display size to save network bytes. Learn more about [responsive images](https://developers.google.com/web/fundamentals/design-and-ui/media/images) and [client hints](https://developers.google.com/web/updates/2015/09/automating-resource-selection-with-client-hints)." }, "appcache-manifest": { "score": true, "displayValue": "", "rawValue": true, "debugString": "", "name": "appcache-manifest", "category": "Offline", "description": "Avoids Application Cache", "helpText": "Application Cache has been [deprecated](https://html.spec.whatwg.org/multipage/browsers.html#offline) by [Service Workers](https://developer.mozilla.org/en-US/docs/Web/API/Service_Worker_API/Using_Service_Workers). Consider implementing an offline solution using the [Cache Storage API](https://developer.mozilla.org/en-US/docs/Web/API/Cache)." }, "dom-size": { "score": 100, "displayValue": "358 nodes", "rawValue": 358, "optimalValue": "1,500 nodes", "extendedInfo": { "formatter": "card", "value": [ { "title": "Total DOM Nodes", "value": "358", "target": "< 1,500 nodes" }, { "title": "DOM Depth", "value": "12", "snippet": "html >\n body >\n div#app >\n div.App >\n div.App__wrap >\n div.App__content >\n div.Items >\n ol.Items__list >\n li.ListItem >\n div.Item__meta >\n span.Item__by >\n a", "target": "< 32" }, { "title": "Maximum Children", "value": "30", "snippet": "Element with most children:\nol.Items__list", "target": "< 60 nodes" } ] }, "name": "dom-size", "category": "Performance", "description": "Avoids an excessive DOM size", "helpText": "Browser engineers recommend pages contain fewer than ~1,500 DOM nodes. The sweet spot is a tree depth < 32 elements and fewer than 60 children/parent element. A large DOM can increase memory, cause longer [style calculations](https://developers.google.com/web/fundamentals/performance/rendering/reduce-the-scope-and-complexity-of-style-calculations), and produce costly [layout reflows](https://developers.google.com/speed/articles/reflow). [Learn more](https://developers.google.com/web/fundamentals/performance/rendering/)." }, "external-anchors-use-rel-noopener": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "urllist", "value": [] }, "name": "external-anchors-use-rel-noopener", "category": "Performance", "description": "Opens external anchors using rel=\"noopener\"", "helpText": "Open new tabs using `rel=\"noopener\"` to improve performance and prevent security vulnerabilities. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/noopener)." }, "geolocation-on-start": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "urllist", "value": [] }, "name": "geolocation-on-start", "category": "UX", "description": "Avoids requesting the geolocation permission on page load", "helpText": "Users are mistrustful of or confused by sites that request their location without context. Consider tying the request to user gestures instead. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/geolocation-on-load)." }, "link-blocking-first-paint": { "score": false, "displayValue": "1 resource delayed first paint by 28ms", "rawValue": false, "extendedInfo": { "formatter": "table", "value": { "results": [ { "url": "…css/style.css", "totalKb": "0 KB", "totalMs": "28ms" } ], "tableHeadings": { "url": "URL", "totalKb": "Size (KB)", "totalMs": "Delayed Paint By (ms)" } } }, "informative": true, "name": "link-blocking-first-paint", "category": "Performance", "description": "Render-blocking Stylesheets", "helpText": "Link elements are blocking the first paint of your page. Consider inlining critical links and deferring non-critical ones. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/blocking-resources)." }, "no-console-time": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "url": "URL", "lineCol": "Line/Col", "isEval": "Eval'd?" } } }, "name": "no-console-time", "category": "JavaScript", "description": "Avoids `console.time()` in its own scripts", "helpText": "Consider using `performance.mark()` and `performance.measure()` from the User Timing API instead. They provide high-precision timestamps, independent of the system clock, and are integrated in the Chrome DevTools Timeline. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/console-time)." }, "no-datenow": { "score": false, "displayValue": "", "rawValue": false, "extendedInfo": { "formatter": "table", "value": { "results": [ { "url": "https://react-hn.appspot.com/vendor.4b459b7e.js", "args": [], "line": 7, "col": 19948, "isEval": false, "isExtension": false }, { "url": "https://react-hn.appspot.com/vendor.4b459b7e.js", "args": [], "line": 7, "col": 19071, "isEval": false, "isExtension": false } ], "tableHeadings": { "url": "URL", "lineCol": "Line/Col", "isEval": "Eval'd?" } } }, "name": "no-datenow", "category": "JavaScript", "description": "Avoids `Date.now()` in its own scripts", "helpText": "Consider using `performance.now()` from the User Timing API instead. It provides high-precision timestamps, independent of the system clock. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/date-now)." }, "no-document-write": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "urllist", "value": [] }, "name": "no-document-write", "category": "Performance", "description": "Avoids `document.write()`", "helpText": "For users on slow connections, external scripts dynamically injected via `document.write()` can delay page load by tens of seconds. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/document-write)." }, "no-mutation-events": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "url": "URL", "lineCol": "Line/Col", "type": "Event", "code": "Snippet" } } }, "name": "no-mutation-events", "category": "JavaScript", "description": "Avoids Mutation Events in its own scripts", "helpText": "Mutation Events are deprecated and harm performance. Consider using Mutation Observers instead. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/mutation-events)." }, "no-old-flexbox": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "url": "URL", "startLine": "Line in the stylesheet / <style>", "location": "Column start/end", "pre": "Snippet" } } }, "name": "no-old-flexbox", "category": "CSS", "description": "Avoids old CSS flexbox", "helpText": "The 2009 spec of Flexbox is deprecated and is 2.3x slower than the latest spec. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/old-flexbox)." }, "no-websql": { "score": true, "displayValue": "", "rawValue": true, "debugString": "", "name": "no-websql", "category": "Offline", "description": "Avoids WebSQL DB", "helpText": "Web SQL is deprecated. Consider using IndexedDB instead. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/web-sql)." }, "notification-on-start": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "urllist", "value": [] }, "name": "notification-on-start", "category": "UX", "description": "Avoids requesting the notification permission on page load", "helpText": "Users are mistrustful of or confused by sites that request to send notifications without context. Consider tying the request to user gestures instead. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/notifications-on-load)." }, "script-blocking-first-paint": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "url": "URL", "totalKb": "Size (KB)", "totalMs": "Delayed Paint By (ms)" } } }, "informative": true, "name": "script-blocking-first-paint", "category": "Performance", "description": "Render-blocking scripts", "helpText": "Script elements are blocking the first paint of your page. Consider inlining critical scripts and deferring non-critical ones. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/blocking-resources)." }, "uses-http2": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "url": "URL", "protocol": "Protocol" } } }, "name": "uses-http2", "category": "Performance", "description": "Uses HTTP/2 for its own resources", "helpText": "HTTP/2 offers many benefits over HTTP/1.1, including binary headers, multiplexing, and server push. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/http2)." }, "uses-passive-event-listeners": { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "url": "URL", "lineCol": "Line/Col", "type": "Type", "pre": "Snippet" } } }, "name": "uses-passive-event-listeners", "category": "JavaScript", "description": "Uses passive listeners to improve scrolling performance", "helpText": "Consider marking your touch and wheel event listeners as `passive` to improve your page's scroll performance. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/passive-event-listeners)." } }, "runtimeConfig": { "environment": [ { "name": "Device Emulation", "enabled": false, "description": "Nexus 5X" }, { "name": "Network Throttling", "enabled": false, "description": "150ms RTT, 1.6Mbps down, 0.7Mbps up" }, { "name": "CPU Throttling", "enabled": false, "description": "5x slowdown" } ], "blockedUrlPatterns": [] }, "aggregations": [ { "name": "Progressive Web App", "description": "These audits validate the aspects of a Progressive Web App. They are a subset of the [PWA Checklist](https://developers.google.com/web/progressive-web-apps/checklist).", "scored": true, "total": 0.906875, "categorizable": true, "score": [ { "overall": 1, "name": "App can load on offline/flaky connections", "description": "Ensuring your web app can respond when the network connection is unavailable or flaky is critical to providing your users a good experience. This is achieved through use of a [Service Worker](https://developers.google.com/web/fundamentals/primers/service-worker/).", "subItems": [ { "score": true, "displayValue": "", "rawValue": true, "name": "service-worker", "category": "Offline", "description": "Registers a Service Worker", "helpText": "The service worker is the technology that enables your app to use many Progressive Web App features, such as offline, add to homescreen, and push notifications. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/registered-service-worker)." }, { "score": true, "displayValue": "", "rawValue": true, "name": "works-offline", "category": "Offline", "description": "Responds with a 200 when offline", "helpText": "If you're building a Progressive Web App, consider using a service worker so that your app can work offline. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/http-200-when-offline)." } ] }, { "overall": 0.755, "name": "Page load performance is fast", "description": "Users notice if sites and apps don't perform well. These top-level metrics capture the most important perceived performance concerns.", "subItems": [ { "score": 93, "displayValue": "1903.6ms", "rawValue": 1903.6, "optimalValue": "1,600ms", "extendedInfo": { "value": { "timestamps": { "navStart": 5987641858569, "fCP": 5987643762143, "fMP": 5987643762181 }, "timings": { "navStart": 0, "fCP": 1903.574, "fMP": 1903.612 } }, "formatter": "null" }, "name": "first-meaningful-paint", "category": "Performance", "description": "First meaningful paint", "helpText": "First meaningful paint measures when the primary content of a page is visible. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/first-meaningful-paint)." }, { "score": 64, "displayValue": "4242", "rawValue": 4242, "optimalValue": "1,250", "extendedInfo": { "formatter": "speedline", "value": { "timings": { "firstVisualChange": 2006, "visuallyComplete": 7648, "speedIndex": 2540.2272597694396, "perceptualSpeedIndex": 4241.957836370474 }, "timestamps": { "firstVisualChange": 5987643832937, "visuallyComplete": 5987649474937, "speedIndex": 5987644367164.26, "perceptualSpeedIndex": 5987646068894.836 }, "frames": [ { "timestamp": 5987641826.937, "progress": 47.98721851076965 }, { "timestamp": 5987643833.684, "progress": 0 }, { "timestamp": 5987643886.949, "progress": 0.10727798594122007 }, { "timestamp": 5987645725.913, "progress": 0.10727798594122007 }, { "timestamp": 5987645741.09, "progress": 0.10727798594122007 }, { "timestamp": 5987645910.182, "progress": 94.22555355364392 }, { "timestamp": 5987646000.386, "progress": 93.21843471574395 }, { "timestamp": 5987646134.825, "progress": 92.56412270729415 }, { "timestamp": 5987646198.926, "progress": 93.46887239213888 }, { "timestamp": 5987646257.77, "progress": 93.06349622048947 }, { "timestamp": 5987646319.492, "progress": 92.85146528355475 }, { "timestamp": 5987646420.551, "progress": 93.64463254959362 }, { "timestamp": 5987646502.884, "progress": 94.42447288826193 }, { "timestamp": 5987646669.898, "progress": 95.44426724912647 }, { "timestamp": 5987646845.207, "progress": 95.77480886510479 }, { "timestamp": 5987646936.984, "progress": 95.34270408602616 }, { "timestamp": 5987646974.703, "progress": 95.34270408602616 }, { "timestamp": 5987647103.923, "progress": 95.20932319786785 }, { "timestamp": 5987647167.411, "progress": 95.10233986301505 }, { "timestamp": 5987647228.743, "progress": 94.71061164566818 }, { "timestamp": 5987647291.399, "progress": 94.22331727951135 }, { "timestamp": 5987647354.366, "progress": 93.71725411688175 }, { "timestamp": 5987647421.922, "progress": 92.99085268800711 }, { "timestamp": 5987647500.876, "progress": 92.41096867850513 }, { "timestamp": 5987647577.113, "progress": 92.92347073307434 }, { "timestamp": 5987647658.579, "progress": 93.06321394854868 }, { "timestamp": 5987647720.306, "progress": 92.85167408858212 }, { "timestamp": 5987647824.149, "progress": 93.70233887455166 }, { "timestamp": 5987647929.067, "progress": 95.67474016800402 }, { "timestamp": 5987648037.238, "progress": 99.31573778946465 }, { "timestamp": 5987648175.362, "progress": 98.88184299876657 }, { "timestamp": 5987648222.791, "progress": 98.55170313872325 }, { "timestamp": 5987648294.437, "progress": 98.45589084854689 }, { "timestamp": 5987648398.34, "progress": 98.44805989179714 }, { "timestamp": 5987648458.672, "progress": 98.44805989179714 }, { "timestamp": 5987648560.845, "progress": 98.31467900363883 }, { "timestamp": 5987648608.905, "progress": 97.8392321567253 }, { "timestamp": 5987648683.639, "progress": 97.33090935941489 }, { "timestamp": 5987648739.325, "progress": 96.88088051936059 }, { "timestamp": 5987648806.713, "progress": 96.32537891209041 }, { "timestamp": 5987648884.169, "progress": 95.51128794025958 }, { "timestamp": 5987648957.862, "progress": 95.75552430951551 }, { "timestamp": 5987649042.866, "progress": 96.3538014895469 }, { "timestamp": 5987649110.439, "progress": 95.93234987259468 }, { "timestamp": 5987649191.179, "progress": 96.47197740281563 }, { "timestamp": 5987649258.077, "progress": 97.22630292317827 }, { "timestamp": 5987649322.852, "progress": 97.75642470542016 }, { "timestamp": 5987649393.601, "progress": 98.73658054866854 }, { "timestamp": 5987649475.521, "progress": 100.00000000000001 } ] } }, "name": "speed-index-metric", "category": "Performance", "description": "Perceptual Speed Index", "helpText": "Speed Index shows how quickly the contents of a page are visibly populated. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/speed-index)." }, { "score": 81, "displayValue": "68.8ms", "rawValue": 68.8, "optimalValue": "50ms", "extendedInfo": { "value": [ { "percentile": 0.5, "time": 16 }, { "percentile": 0.75, "time": 16.34444855476577 }, { "percentile": 0.9, "time": 68.82830000591343 }, { "percentile": 0.99, "time": 449.40702000236706 }, { "percentile": 1, "time": 508.3710000000019 } ], "formatter": "null" }, "name": "estimated-input-latency", "category": "Performance", "description": "Estimated Input Latency", "helpText": "The score above is an estimate of how long your app takes to respond to user input, in milliseconds. There is a 90% probability that a user encounters this amount of latency, or less. 10% of the time a user can expect additional latency. If your score is higher than Lighthouse's target score, users may perceive your app as laggy. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/estimated-input-latency)." }, { "score": 64, "displayValue": "4051.6ms", "rawValue": 4051.6, "optimalValue": "5,000ms", "extendedInfo": { "value": { "timings": { "fMP": 1903.6, "visuallyReady": 4051.613, "timeToInteractive": 4051.613 }, "timestamps": { "fMP": 5987643762181, "visuallyReady": 5987645910182, "timeToInteractive": 5987645910182 }, "expectedLatencyAtTTI": 20.457, "foundLatencies": [ { "estLatency": 20.456749952316258, "startTime": "4051.6" } ] }, "formatter": "null" }, "name": "time-to-interactive", "category": "Performance", "description": "Time To Interactive (alpha)", "helpText": "Time to Interactive identifies the time at which your app appears to be ready enough to interact with. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/time-to-interactive)." } ] }, { "overall": 1, "name": "Site is progressively enhanced", "description": "Progressive enhancement means that everyone can access the basic content and functionality of a page in any browser, and those without certain browser features may receive a reduced but still functional experience.", "subItems": [ { "score": true, "displayValue": "", "rawValue": true, "name": "without-javascript", "category": "JavaScript", "description": "Contains some content when JavaScript is not available", "helpText": "Your app should display some content when JavaScript is disabled, even if it's just a warning to the user that JavaScript is required to use the app. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/no-js)." } ] }, { "overall": 0.5, "name": "Network connection is secure", "description": "Security is an important part of the web for both developers and users. Moving forward, Transport Layer Security (TLS) support will be required for many APIs.", "subItems": [ { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "urllist", "value": [] }, "name": "is-on-https", "category": "Security", "description": "Uses HTTPS", "helpText": "All sites should be protected with HTTPS, even ones that don't handle sensitive data. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/https)." }, { "score": false, "displayValue": "", "rawValue": false, "name": "redirects-http", "category": "Security", "description": "Redirects HTTP traffic to HTTPS", "helpText": "If you've already set up HTTPS, make sure that you redirect all HTTP traffic to HTTPS. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/http-redirects-to-https)." } ] }, { "overall": 1, "name": "User can be prompted to Add to Homescreen", "description": "While users can manually add your site to their homescreen in the browser menu, the [prompt (aka app install banner)](https://developers.google.com/web/updates/2015/03/increasing-engagement-with-app-install-banners-in-chrome-for-android) will proactively prompt the user to install the app if the below requirements are met and the user has visited your site at least twice (with at least five minutes between visits).", "subItems": [ { "score": true, "displayValue": "", "rawValue": true, "name": "service-worker", "category": "Offline", "description": "Registers a Service Worker", "helpText": "The service worker is the technology that enables your app to use many Progressive Web App features, such as offline, add to homescreen, and push notifications. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/registered-service-worker)." }, { "score": true, "displayValue": "", "rawValue": true, "name": "manifest-exists", "category": "Manifest", "description": "Manifest exists", "helpText": "The web app manifest is the technology that enables users to add your web app to their homescreen. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-exists)." }, { "score": true, "displayValue": "", "rawValue": true, "name": "manifest-start-url", "category": "Manifest", "description": "Manifest contains `start_url`", "helpText": "Add a `start_url` to instruct the browser to launch a specific URL whenever your app is launched from a homescreen. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-contains-start_url)." }, { "score": true, "displayValue": "found sizes: 152x152, 144x144, 192x192, 384x384", "rawValue": true, "name": "manifest-icons-min-144", "category": "Manifest", "description": "Manifest contains icons at least 144px" }, { "score": true, "displayValue": "", "rawValue": true, "name": "manifest-short-name", "category": "Manifest", "description": "Manifest contains `short_name`", "helpText": "The `short_name` property is a requirement for Add To Homescreen. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-contains-short_name)." } ] }, { "overall": 1, "name": "Installed web app will launch with custom splash screen", "description": "A default splash screen will be constructed, but meeting these requirements guarantee a high-quality and customizable [splash screen](https://developers.google.com/web/updates/2015/10/splashscreen) the user sees between tapping the home screen icon and your app's first paint.", "subItems": [ { "score": true, "displayValue": "", "rawValue": true, "name": "manifest-exists", "category": "Manifest", "description": "Manifest exists", "helpText": "The web app manifest is the technology that enables users to add your web app to their homescreen. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-exists)." }, { "score": true, "displayValue": "", "rawValue": true, "name": "manifest-name", "category": "Manifest", "description": "Manifest contains `name`", "helpText": "The `name` property identifies your app and is required. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-contains-name)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "value": "#4CC1FC", "formatter": "null" }, "name": "manifest-background-color", "category": "Manifest", "description": "Manifest contains `background_color`", "helpText": "When your app launches from a user's homescreen, the browser uses `background_color` to paint the background of the browser while your app loads for a smooth transition experience. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-contains-background_color)." }, { "score": true, "displayValue": "", "rawValue": true, "name": "manifest-theme-color", "category": "Manifest", "description": "Manifest contains `theme_color`", "helpText": "Add a `theme_color` to set the color of the browser's address bar. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-contains-theme_color)." }, { "score": true, "displayValue": "found sizes: 192x192, 384x384", "rawValue": true, "name": "manifest-icons-min-192", "category": "Manifest", "description": "Manifest contains icons at least 192px", "helpText": "A 192px icon ensures that your app's icon displays well on the homescreens of the largest mobile devices. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-contains-192px-icon)." } ] }, { "overall": 1, "name": "Address bar matches brand colors", "description": "The browser address bar can be themed to match your site. A `theme-color` [meta tag](https://developers.google.com/web/updates/2014/11/Support-for-theme-color-in-Chrome-39-for-Android) will upgrade the address bar when a user browses the site, and the [manifest theme-color](https://developers.google.com/web/updates/2015/08/using-manifest-to-set-sitewide-theme-color) will apply the same theme site-wide once it's been added to homescreen.", "subItems": [ { "score": true, "displayValue": "", "rawValue": true, "name": "manifest-exists", "category": "Manifest", "description": "Manifest exists", "helpText": "The web app manifest is the technology that enables users to add your web app to their homescreen. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-exists)." }, { "score": true, "displayValue": "#222222", "rawValue": true, "name": "theme-color-meta", "category": "HTML", "description": "Has a `<meta name=\"theme-color\">` tag" }, { "score": true, "displayValue": "", "rawValue": true, "name": "manifest-theme-color", "category": "Manifest", "description": "Manifest contains `theme_color`", "helpText": "Add a `theme_color` to set the color of the browser's address bar. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-contains-theme_color)." } ] }, { "overall": 1, "name": "Design is mobile-friendly", "description": "Users increasingly experience your app on mobile devices, so it's important to ensure that the experience can adapt to smaller screens.", "subItems": [ { "score": true, "displayValue": "", "rawValue": true, "debugString": "", "name": "viewport", "category": "Mobile Friendly", "description": "Has a `<meta name=\"viewport\">` tag with `width` or `initial-scale`", "helpText": "Add a viewport meta tag to optimize your app for mobile screens. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/has-viewport-meta-tag)." }, { "score": true, "displayValue": "", "rawValue": true, "debugString": "", "name": "content-width", "category": "Mobile Friendly", "description": "Content is sized correctly for the viewport", "helpText": "If the width of your app's content doesn't match the width of the viewport, your app might not be optimized for mobile screens. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/content-sized-correctly-for-viewport)." } ] } ] }, { "name": "Best Practices", "description": "We've compiled some recommendations for modernizing your web app and avoiding performance pitfalls. These audits do not affect your score but are worth a look.", "scored": false, "total": null, "categorizable": true, "score": [ { "overall": 1, "name": "Using modern offline features", "subItems": [ { "score": true, "displayValue": "", "rawValue": true, "debugString": "", "name": "appcache-manifest", "category": "Offline", "description": "Avoids Application Cache", "helpText": "Application Cache has been [deprecated](https://html.spec.whatwg.org/multipage/browsers.html#offline) by [Service Workers](https://developer.mozilla.org/en-US/docs/Web/API/Service_Worker_API/Using_Service_Workers). Consider implementing an offline solution using the [Cache Storage API](https://developer.mozilla.org/en-US/docs/Web/API/Cache)." }, { "score": true, "displayValue": "", "rawValue": true, "debugString": "", "name": "no-websql", "category": "Offline", "description": "Avoids WebSQL DB", "helpText": "Web SQL is deprecated. Consider using IndexedDB instead. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/web-sql)." } ] }, { "overall": 1, "name": "Using modern protocols", "subItems": [ { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "urllist", "value": [] }, "name": "is-on-https", "category": "Security", "description": "Uses HTTPS", "helpText": "All sites should be protected with HTTPS, even ones that don't handle sensitive data. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/https)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "url": "URL", "protocol": "Protocol" } } }, "name": "uses-http2", "category": "Performance", "description": "Uses HTTP/2 for its own resources", "helpText": "HTTP/2 offers many benefits over HTTP/1.1, including binary headers, multiplexing, and server push. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/http2)." } ] }, { "overall": 1, "name": "Using modern CSS features", "subItems": [ { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "url": "URL", "startLine": "Line in the stylesheet / <style>", "location": "Column start/end", "pre": "Snippet" } } }, "name": "no-old-flexbox", "category": "CSS", "description": "Avoids old CSS flexbox", "helpText": "The 2009 spec of Flexbox is deprecated and is 2.3x slower than the latest spec. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/old-flexbox)." } ] }, { "overall": 1, "name": "Using modern JavaScript features", "subItems": [ { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "url": "URL", "lineCol": "Line/Col", "type": "Type", "pre": "Snippet" } } }, "name": "uses-passive-event-listeners", "category": "JavaScript", "description": "Uses passive listeners to improve scrolling performance", "helpText": "Consider marking your touch and wheel event listeners as `passive` to improve your page's scroll performance. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/passive-event-listeners)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "url": "URL", "lineCol": "Line/Col", "type": "Event", "code": "Snippet" } } }, "name": "no-mutation-events", "category": "JavaScript", "description": "Avoids Mutation Events in its own scripts", "helpText": "Mutation Events are deprecated and harm performance. Consider using Mutation Observers instead. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/mutation-events)." } ] }, { "overall": 1, "name": "Avoiding APIs that harm the user experience", "subItems": [ { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "urllist", "value": [] }, "name": "no-document-write", "category": "Performance", "description": "Avoids `document.write()`", "helpText": "For users on slow connections, external scripts dynamically injected via `document.write()` can delay page load by tens of seconds. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/document-write)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "urllist", "value": [] }, "name": "external-anchors-use-rel-noopener", "category": "Performance", "description": "Opens external anchors using rel=\"noopener\"", "helpText": "Open new tabs using `rel=\"noopener\"` to improve performance and prevent security vulnerabilities. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/noopener)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "urllist", "value": [] }, "name": "geolocation-on-start", "category": "UX", "description": "Avoids requesting the geolocation permission on page load", "helpText": "Users are mistrustful of or confused by sites that request their location without context. Consider tying the request to user gestures instead. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/geolocation-on-load)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "urllist", "value": [] }, "name": "notification-on-start", "category": "UX", "description": "Avoids requesting the notification permission on page load", "helpText": "Users are mistrustful of or confused by sites that request to send notifications without context. Consider tying the request to user gestures instead. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/notifications-on-load)." } ] }, { "overall": 0, "name": "Avoiding deprecated APIs and browser interventions", "subItems": [ { "score": false, "displayValue": "1 warning found", "rawValue": false, "extendedInfo": { "formatter": "urllist", "value": [ { "label": "line: 4", "url": "https://s-usc1c-nss-137.firebaseio.com/.lp?dframe=t&id=106465&pw=9K9EEyIUTY&ns=hacker-news", "code": "Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check https://xhr.spec.whatwg.org/.", "source": "deprecation", "level": "warning", "text": "Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. 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[Learn more](https://www.chromestatus.com/features#deprecated)." } ] }, { "overall": 1, "name": "Accessibility", "subItems": [ { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "aria-allowed-attr", "category": "Accessibility", "description": "Element aria-* attributes are allowed for this role", "helpText": "Each ARIA `role` supports a specific subset of `aria-*` attributes. Mismatching these invalidates the `aria-*` attributes. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/aria-allowed-attributes)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "aria-required-attr", "category": "Accessibility", "description": "Elements with ARIA roles have the required aria-* attributes", "helpText": "Some ARIA roles have required attributes that describe the state of the element to screen readers. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/required-aria-attributes)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "aria-valid-attr", "category": "Accessibility", "description": "Element aria-* attributes are valid and not misspelled or non-existent.", "helpText": "Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid names. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/valid-aria-attributes)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "aria-valid-attr-value", "category": "Accessibility", "description": "Element aria-* attributes have valid values", "helpText": "Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid values. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/valid-aria-values)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "color-contrast", "category": "Accessibility", "description": "Background and foreground colors have a sufficient contrast ratio", "helpText": "Low-contrast text is difficult or impossible for many users to read. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/contrast-ratio)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "image-alt", "category": "Accessibility", "description": "Every image element has an alt attribute", "helpText": "Screen reader users rely on `alt` text to provide descriptions of images. It's also used as fallback content when an image fails to load. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/alt-attribute)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "label", "category": "Accessibility", "description": "Every form element has a label", "helpText": "Labels ensure that form controls are announced properly by assistive technologies, like screen readers. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/form-labels)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "accessibility" }, "name": "tabindex", "category": "Accessibility", "description": "No element has a `tabindex` attribute greater than 0", "helpText": "A value greater than 0 implies an explicit navigation ordering. Although technically valid, this often creates frustrating experiences for users who rely on assistive technologies. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/tabindex)." } ] }, { "overall": 1, "name": "Other", "subItems": [ { "score": true, "displayValue": "", "rawValue": true, "name": "manifest-short-name-length", "category": "Manifest", "description": "Manifest's `short_name` won't be truncated when displayed on homescreen", "helpText": "Make your app's `short_name` less than 12 characters to ensure that it's not truncated on homescreens. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-short_name-is-not-truncated)." }, { "score": true, "displayValue": "standalone", "rawValue": true, "name": "manifest-display", "category": "Manifest", "description": "Manifest's `display` property is set", "helpText": "Set the `display` property to specify how your app launches from the homescreen. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/manifest-has-display-set)." } ] } ] }, { "name": "Performance", "description": "These encapsulate your app's performance.", "scored": false, "total": null, "categorizable": false, "score": [ { "overall": 0.75, "subItems": [ { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "preview": "", "url": "URL", "totalKb": "Original", "webpSavings": "WebP Savings", "jpegSavings": "JPEG Savings" } } }, "informative": true, "name": "uses-optimized-images", "category": "Images", "description": "Unoptimized images", "helpText": "Images should be optimized to save network bytes. The following images could have smaller file sizes when compressed with [WebP](https://developers.google.com/speed/webp/) or JPEG at 80 quality. [Learn more about image optimization](https://developers.google.com/web/fundamentals/performance/optimizing-content-efficiency/image-optimization)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "preview": "", "url": "URL", "totalKb": "Original", "potentialSavings": "Potential Savings" } } }, "informative": true, "name": "uses-responsive-images", "category": "Images", "description": "Oversized Images", "helpText": "Image sizes served should be based on the device display size to save network bytes. Learn more about [responsive images](https://developers.google.com/web/fundamentals/design-and-ui/media/images) and [client hints](https://developers.google.com/web/updates/2015/09/automating-resource-selection-with-client-hints)." }, { "score": false, "displayValue": "6", "rawValue": false, "optimalValue": 0, "extendedInfo": { "formatter": "criticalRequestChains", "value": { "15692.1": { "request": { "url": "https://react-hn.appspot.com/", "startTime": 5987641.90899, "endTime": 5987643.206606, "responseReceivedTime": 5987643.165806, "transferSize": 4794 }, "children": { "15692.2": { "request": { "url": "https://react-hn.appspot.com/css/style.css", "startTime": 5987643.232062, "endTime": 5987643.635266, "responseReceivedTime": 5987643.612755, "transferSize": 1987 }, "children": {} }, "15692.3": { "request": { "url": "https://react-hn.appspot.com/img/logo.png", "startTime": 5987643.234548, "endTime": 5987643.77499, "responseReceivedTime": 5987643.769936, "transferSize": 380 }, "children": {} }, "15692.6": { "request": { "url": "https://react-hn.appspot.com/manifest.d41d8cd9.js", "startTime": 5987643.638648, "endTime": 5987644.024285, "responseReceivedTime": 5987644.017136, "transferSize": 1536 }, "children": {} }, "15692.5": { "request": { "url": "https://react-hn.appspot.com/core.js", "startTime": 5987643.637573, "endTime": 5987644.033014, "responseReceivedTime": 5987644.026095, "transferSize": 684 }, "children": {} }, "15692.8": { "request": { "url": "https://react-hn.appspot.com/app.c8553140.js", "startTime": 5987643.64225, "endTime": 5987644.131681, "responseReceivedTime": 5987644.035999, "transferSize": 10055 }, "children": {} }, "15692.7": { "request": { "url": "https://react-hn.appspot.com/vendor.4b459b7e.js", "startTime": 5987643.641492, "endTime": 5987645.048714, "responseReceivedTime": 5987644.135171, "transferSize": 114502 }, "children": {} } } }, "15692.63": { "request": { "url": "https://react-hn.appspot.com/img/apple-touch-icon-144x144.png", "startTime": 5987646.945635, "endTime": 5987647.853953, "responseReceivedTime": 5987647.834083, "transferSize": 3033 }, "children": {} }, "15692.62": { "request": { "url": "https://react-hn.appspot.com/img/android-chrome-192x192.png", "startTime": 5987646.944652, "endTime": 5987647.986053, "responseReceivedTime": 5987647.98236, "transferSize": 3833 }, "children": {} }, "15692.61": { "request": { "url": "https://react-hn.appspot.com/manifest.json", "startTime": 5987646.926169, "endTime": 5987648.092081, "responseReceivedTime": 5987648.089057, "transferSize": 533 }, "children": {} }, "15692.65": { "request": { "url": "https://react-hn.appspot.com/img/android-chrome-144x144.png", "startTime": 5987648.109951, "endTime": 5987648.656293, "responseReceivedTime": 5987648.65065, "transferSize": 3019 }, "children": {} } } }, "informative": true, "name": "critical-request-chains", "category": "Performance", "description": "Critical Request Chains", "helpText": "The Critical Request Chains below show you what resources are required for first render of this page. Improve page load by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/critical-request-chains)." }, { "score": false, "displayValue": "1 resource delayed first paint by 28ms", "rawValue": false, "extendedInfo": { "formatter": "table", "value": { "results": [ { "url": "…css/style.css", "totalKb": "0 KB", "totalMs": "28ms" } ], "tableHeadings": { "url": "URL", "totalKb": "Size (KB)", "totalMs": "Delayed Paint By (ms)" } } }, "informative": true, "name": "link-blocking-first-paint", "category": "Performance", "description": "Render-blocking Stylesheets", "helpText": "Link elements are blocking the first paint of your page. Consider inlining critical links and deferring non-critical ones. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/blocking-resources)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "url": "URL", "totalKb": "Size (KB)", "totalMs": "Delayed Paint By (ms)" } } }, "informative": true, "name": "script-blocking-first-paint", "category": "Performance", "description": "Render-blocking scripts", "helpText": "Script elements are blocking the first paint of your page. Consider inlining critical scripts and deferring non-critical ones. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/blocking-resources)." }, { "score": 100, "displayValue": "Total size was 154 KB", "rawValue": 157486, "optimalValue": "1,600 KB", "extendedInfo": { "formatter": "table", "value": { "results": [ { "url": "/vendor.4b459b7e.js", "totalBytes": 114502, "totalKb": "112 KB", "totalMs": "820ms" }, { "url": "/analytics.js", "totalBytes": 12542, "totalKb": "12 KB", "totalMs": "90ms" }, { "url": "/app.c8553140.js", "totalBytes": 10055, "totalKb": "10 KB", "totalMs": "70ms" }, { "url": "/", "totalBytes": 4794, "totalKb": "5 KB", "totalMs": "30ms" }, { "url": "…img/android-chrome-192x192.png", "totalBytes": 3833, "totalKb": "4 KB", "totalMs": "30ms" }, { "url": "…img/apple-touch-icon-144x144.png", "totalBytes": 3033, "totalKb": "3 KB", "totalMs": "20ms" }, { "url": "…img/android-chrome-144x144.png", "totalBytes": 3019, "totalKb": "3 KB", "totalMs": "20ms" }, { "url": "…css/style.css", "totalBytes": 1987, "totalKb": "2 KB", "totalMs": "10ms" }, { "url": "/manifest.d41d8cd9.js", "totalBytes": 1536, "totalKb": "2 KB", "totalMs": "10ms" }, { "url": "/core.js", "totalBytes": 684, "totalKb": "1 KB", "totalMs": "0ms" } ], "tableHeadings": { "url": "URL", "totalKb": "Total Size", "totalMs": "Transfer Time" } } }, "informative": true, "name": "total-byte-weight", "category": "Network", "description": "Avoids enormous network payloads", "helpText": "Network transfer size [costs users real dollars](https://whatdoesmysitecost.com/) and is [highly correlated](http://httparchive.org/interesting.php#onLoad) with long load times. Try to find ways to reduce the size of required files." }, { "score": 100, "displayValue": "358 nodes", "rawValue": 358, "optimalValue": "1,500 nodes", "extendedInfo": { "formatter": "card", "value": [ { "title": "Total DOM Nodes", "value": "358", "target": "< 1,500 nodes" }, { "title": "DOM Depth", "value": "12", "snippet": "html >\n body >\n div#app >\n div.App >\n div.App__wrap >\n div.App__content >\n div.Items >\n ol.Items__list >\n li.ListItem >\n div.Item__meta >\n span.Item__by >\n a", "target": "< 32" }, { "title": "Maximum Children", "value": "30", "snippet": "Element with most children:\nol.Items__list", "target": "< 60 nodes" } ] }, "name": "dom-size", "category": "Performance", "description": "Avoids an excessive DOM size", "helpText": "Browser engineers recommend pages contain fewer than ~1,500 DOM nodes. The sweet spot is a tree depth < 32 elements and fewer than 60 children/parent element. A large DOM can increase memory, cause longer [style calculations](https://developers.google.com/web/fundamentals/performance/rendering/reduce-the-scope-and-complexity-of-style-calculations), and produce costly [layout reflows](https://developers.google.com/speed/articles/reflow). [Learn more](https://developers.google.com/web/fundamentals/performance/rendering/)." }, { "score": true, "displayValue": "0", "rawValue": true, "extendedInfo": { "formatter": "userTimings", "value": [] }, "informative": true, "name": "user-timings", "category": "Performance", "description": "User Timing marks and measures", "helpText": "Consider instrumenting your app with the User Timing API to create custom, real-world measurements of key user experiences. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/user-timing)." } ] } ] }, { "name": "Fancier stuff", "description": "A list of newer features that you could be using in your app. These audits do not affect your score and are just suggestions.", "scored": false, "additional": true, "total": null, "categorizable": true, "score": [ { "overall": 0.5, "name": "New JavaScript features", "subItems": [ { "score": false, "displayValue": "", "rawValue": false, "extendedInfo": { "formatter": "table", "value": { "results": [ { "url": "https://react-hn.appspot.com/vendor.4b459b7e.js", "args": [], "line": 7, "col": 19948, "isEval": false, "isExtension": false }, { "url": "https://react-hn.appspot.com/vendor.4b459b7e.js", "args": [], "line": 7, "col": 19071, "isEval": false, "isExtension": false } ], "tableHeadings": { "url": "URL", "lineCol": "Line/Col", "isEval": "Eval'd?" } } }, "name": "no-datenow", "category": "JavaScript", "description": "Avoids `Date.now()` in its own scripts", "helpText": "Consider using `performance.now()` from the User Timing API instead. It provides high-precision timestamps, independent of the system clock. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/date-now)." }, { "score": true, "displayValue": "", "rawValue": true, "extendedInfo": { "formatter": "table", "value": { "results": [], "tableHeadings": { "url": "URL", "lineCol": "Line/Col", "isEval": "Eval'd?" } } }, "name": "no-console-time", "category": "JavaScript", "description": "Avoids `console.time()` in its own scripts", "helpText": "Consider using `performance.mark()` and `performance.measure()` from the User Timing API instead. They provide high-precision timestamps, independent of the system clock, and are integrated in the Chrome DevTools Timeline. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/console-time)." } ] } ] } ] }