C — https://jestjs.io | BeaverCheck Audit

Site Health

Score: 76 / 100 Same as last audit

Based on 8 categories, 0 sections

How is this calculated?

The overall score is a weighted average of individual category scores. Categories with more impact on user experience and security carry more weight.

Performance 25%Security 25%Accessibility 15%SEO 10%Infrastructure 10%Compliance 8%Content 5%Sustainability 2%

Weights reflect general web best practices. Individual needs may differ.

Top Priorities (5)

Content-Security-Policy header is missing

Security › Security Headers

No Content-Security-Policy header found

Security › Content Security Policy

4 image(s) missing alt attribute

Accessibility › Alt Text Quality

No <main> landmark found

Accessibility › Landmark Structure

No H1 heading found

Accessibility › Heading Hierarchy

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Markdown

[![BeaverCheck](https://beavercheck.com/badge?url=https%3A%2F%2Fjestjs.io)](https://beavercheck.com/results/b0f5b92d-007d-4cad-8736-1da3f2216d9a)

HTML

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Recent Trends

Performance stable →

TTFB stable →

273ms

FCP stable →

1.1s

LCP stable →

7.1s

Press ? for shortcuts

Lighthouse Scores

Industry-standard audits powered by Google Lighthouse.

61 +5

Performance

Accessibility

Best Practices

SEO

Core Web Vitals

Key metrics that affect user experience.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

1.07 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

7.09 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

578 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.000

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

2.72 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

8.70 s

Detailed Report

Audit breakdown by category with detailed findings.

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Request	Cache TTL	Transfer Size
jestjs.io/img/content/feature-fast.png	14400.0 s	308.2 KiB
jestjs.io/img/content/feature-coverage.png	14400.0 s	203.4 KiB
jestjs.io/img/content/matchers/toBe.png	14400.0 s	188.6 KiB
jestjs.io/img/content/feature-mocking.png	14400.0 s	188.3 KiB
jestjs.io/assets/js/main.17432a57.js	14400.0 s	140.4 KiB
jestjs.io/img/logos/instagram.png	14400.0 s	55.4 KiB
jestjs.io/img/logos/spotify.png	14400.0 s	39.0 KiB
jestjs.io/assets/js/8155.4644b154.js	14400.0 s	33.0 KiB
jestjs.io/img/logos/airbnb.png	14400.0 s	32.0 KiB
jestjs.io/assets/css/styles.a07fbb26.css	14400.0 s	27.7 KiB
www.google-analytics.com/analytics.js	7200.0 s	20.9 KiB
jestjs.io/img/logos/nyt.png	14400.0 s	10.7 KiB
i.ytimg.com/vi/cAKYQpTC7MA/hqdefault.jpg	7200.0 s	7.8 KiB
images.opencollective.com/datadog/5301801/logo.png	86400.0 s	13.8 KiB
jestjs.io/assets/js/1646.9c736360.js	14400.0 s	7.4 KiB
jestjs.io/assets/js/c4f5d8e4.f64f7276.js	14400.0 s	6.3 KiB
jestjs.io/assets/js/runtime~main.ffe131c7.js	14400.0 s	5.6 KiB
images.opencollective.com/airbnb/d327d66/logo.png	86400.0 s	7.9 KiB
jestjs.io/img/logos/facebook.png	14400.0 s	4.0 KiB
images.opencollective.com/principal/431e690/logo.png	86400.0 s	6.3 KiB
jestjs.io/img/openjs_foundation-logo-horizontal-color-dark_background.svg	14400.0 s	2.5 KiB
jestjs.io/assets/js/3048.004dfdb5.js	14400.0 s	2.4 KiB
jestjs.io/img/logos/twitter.png	14400.0 s	1.8 KiB
jestjs.io/img/logos/thordata.svg	14400.0 s	1.4 KiB
jestjs.io/assets/js/a7456010.2a75c070.js	14400.0 s	293 B

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

More than 4 preconnect connections were found. These should be used sparingly and only to the most important origins.

description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.

title: Preconnected origins

description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.

title: Preconnect candidates

value: No additional origins are good candidates for preconnecting

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

URL	Transfer Size	Duration
jestjs.io/assets/css/styles.a07fbb26.css	27.7 KiB	300 ms

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

	URL	Resource Size	Est Savings
Instagram `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/instagram.png	55.2 KiB	52.4 KiB
Spotify `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/spotify.png	38.8 KiB	36.0 KiB
Airbnb `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/airbnb.png	31.8 KiB	30.1 KiB
Datadog's avatar `div.opencollective > div.opencollective-avatars > a.sponsor-item > img.sponsor-avatar`	images.opencollective.com/datadog/5301801/logo.png	13.2 KiB	10.7 KiB
The New York Times `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/nyt.png	10.6 KiB	8.5 KiB
Airbnb's avatar `div.opencollective > div.opencollective-avatars > a.sponsor-item > img.sponsor-avatar`	images.opencollective.com/airbnb/d327d66/logo.png	7.2 KiB	4.6 KiB

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

TTI

Diagnostics

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Estimated savings: 0.0 ms 17.9 KiB

URL	Transfer Size	Est Savings
jestjs.io/assets/css/styles.a07fbb26.css	27.5 KiB	17.9 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Estimated savings: 150 ms 158.2 KiB

URL	Transfer Size	Est Savings
www.googletagmanager.com/gtag/js?id=G-9V0LCYENMT&cx=c&gtm=4e6411	144.3 KiB	62.7 KiB
www.googletagmanager.com/gtag/js?id=UA-44373548-17	123.4 KiB	62.6 KiB
jestjs.io/assets/js/main.17432a57.js	140.3 KiB	32.9 KiB

Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to reduce Javascript execution time.

URL	Total CPU Time	Script Evaluation	Script Parse
jestjs.io/	2.6 s	27 ms	3.9 ms
jestjs.io/assets/js/main.17432a57.js	1.2 s	1.0 s	72 ms
Unattributable	524 ms	80 ms	0.0 ms
www.googletagmanager.com/gtag/js?id=UA-44373548-17	277 ms	227 ms	49 ms
www.googletagmanager.com/gtag/js?id=G-9V0LCYENMT&cx=c&gtm=4e6411	214 ms	154 ms	58 ms
jestjs.io/assets/js/8155.4644b154.js	74 ms	59 ms	15 ms
www.google-analytics.com/analytics.js	72 ms	56 ms	7.0 ms

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work

Category	Time Spent
Script Evaluation	1.7 s
Other	1.2 s
Style & Layout	1.1 s
Rendering	872 ms
Script Parsing & Compilation	219 ms
Garbage Collection	38 ms
Parse HTML & CSS	36 ms

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

	URL
Airbnb `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/airbnb.png
Facebook `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/facebook.png
Instagram `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/instagram.png
The New York Times `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/nyt.png
Spotify `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/spotify.png
OpenJS Foundation Logo `div.footer__bottom > div.margin-bottom--sm > a.footerLogoLink_tutC > img.footer__logo`	jestjs.io/img/openjs_foundation-logo-horizontal-color-dark_background.svg
Twitter `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/twitter.png

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Layout shift culprits

●Document request latency

●Optimize DOM size

●Font display

●Forced reflow

●LCP breakdown

●Modern HTTP

●Optimize viewport for mobile

●Minify CSS

●Minify JavaScript

●Avoids enormous network payloads Total size was 1,670 KiB

●User Timing marks and measures 5 user timings

●Avoid long main-thread tasks 10 long tasks found

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 20 ms

●Server Backend Latencies 20 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Avoid multiple page redirects

●Initial server response time was short Root document took 20 ms

○INP breakdown

○LCP request discovery

○Avoid non-composited animations

○Avoid large layout shifts

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Failing Elements
JEST `div.navbar__inner > div.theme-layout-navbar-left > a.navbar__brand > b.navbar__title`
PASS `div.jest-card-hitslop > div.jest-card > div.jest-card-front > div.jest-card-label`
JEST `div.jest-card-hitslop > div.jest-card > div.jest-card-front > div.jest-card-label`
PASS `div.jest-card-hitslop > div.jest-card > div.jest-card-front > div.jest-card-label`
zero config `h2 > div > span > p`
snapshots `h2 > div > span > p`
isolated `h2 > div > span > p`
great api `h2 > div > span > p`
FAST AND SAFE `h2 > div > span > p`
CODE COVERAGE `h2 > div > span > p`
--coverage `span > p > a > code`
Mock Functions `div > span > p > a`
GREAT EXCEPTIONS `h2 > div > span > p`
toBeCloseTo `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toEqual `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toStrictEqual `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toHaveProperty `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toMatchSnapshot `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toThrowError `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
PHILOSOPHY `div.wrapperV1 > div.blockElement > div.blockContent > h2`
Jest and Delightful JavaScript Testing `div > span > p > a`
Building High-Quality JavaScript Tools `div > span > p > a`
Jest as a Platform `div > span > p > a`
OPEN COLLECTIVE `div.wrapperV1 > div.yellow > div.blockContent > h2`
gold sponsors `div.yellow > div.blockContent > div.opencollective > h3`
featured sponsors `div.yellow > div.blockContent > div.opencollective > h3`
Join 600+ donors `div.blockContent > div.opencollective > p > a`
opencollective.com `div.blockContent > div.opencollective > p > a`
WHO USES JEST? `div.wrapperV1 > div.yellow > div.blockContent > h2`
100m+ million `div > span > p > a`
15,000,000 `div > span > p > a`
OpenJS Foundation `div.footer__bottom > div.footer__copyright > p > a`
OpenJS Foundation `div.footer__bottom > div.footer__copyright > p > a`
OpenJS Foundation `div.footer__bottom > div.footer__copyright > p > a`
Trademark Policy `div.footer__bottom > div.footer__copyright > p > a`
Trademark List `div.footer__bottom > div.footer__copyright > p > a`
list of OpenJS Foundation trademarks `div.footer__bottom > div.footer__copyright > p > a`
The OpenJS Foundation `div.footer__bottom > div.footer__copyright > p > a`
Terms of Use `div.footer__bottom > div.footer__copyright > p > a`
Privacy Policy `div.footer__bottom > div.footer__copyright > p > a`
Bylaws `div.footer__bottom > div.footer__copyright > p > a`
Code of Conduct `div.footer__bottom > div.footer__copyright > p > a`
Trademark Policy `div.footer__bottom > div.footer__copyright > p > a`
Trademark List `div.footer__bottom > div.footer__copyright > p > a`
Cookie Policy `div.footer__bottom > div.footer__copyright > p > a`

Low-contrast text is difficult or impossible for many users to read. Link text that is discernible improves the experience for users with low vision. Learn how to make links distinguishable.

Failing Elements
OpenJS Foundation `div.footer__bottom > div.footer__copyright > p > a`
OpenJS Foundation `div.footer__bottom > div.footer__copyright > p > a`
OpenJS Foundation `div.footer__bottom > div.footer__copyright > p > a`
Trademark Policy `div.footer__bottom > div.footer__copyright > p > a`
Trademark List `div.footer__bottom > div.footer__copyright > p > a`
list of OpenJS Foundation trademarks `div.footer__bottom > div.footer__copyright > p > a`

These are opportunities to improve the legibility of your content.

Best practices

One main landmark helps screen reader users navigate a web page. Learn more about landmarks.

Failing Elements
html.plugin-pages `html.plugin-pages`

These items highlight common accessibility best practices.

○Interactive controls are keyboard focusable

○Interactive elements indicate their purpose and state

○The page has a logical tab order

○Visual order on the page follows DOM order

○User focus is not accidentally trapped in a region

○The user's focus is directed to new content added to the page

○HTML5 landmark elements are used to improve navigation

○Offscreen content is hidden from assistive technology

○Custom controls have associated labels

○Custom controls have ARIA roles

●`[aria-*]` attributes match their roles

●`[aria-hidden="true"]` is not present on the document `<body>`

●`[role]`s have all required `[aria-*]` attributes

●`[role]` values are valid

●`[aria-*]` attributes have valid values

●`[aria-*]` attributes are valid and not misspelled

●Buttons have an accessible name

●Image elements have `[alt]` attributes

●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.

●ARIA attributes are used as specified for the element's role

●`[aria-hidden="true"]` elements do not contain focusable descendents

●Elements use only permitted ARIA attributes

●Document has a `<title>` element

●`<html>` element has a `[lang]` attribute

●`<html>` element has a valid value for its `[lang]` attribute

●Links have a discernible name

●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).

●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements

●Touch targets have sufficient size and spacing.

●Heading elements appear in a sequentially-descending order

●Deprecated ARIA roles were not used

○`[accesskey]` values are unique

○`button`, `link`, and `menuitem` elements have accessible names

○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.

○ARIA input fields have accessible names

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.

○`[role]`s are contained by their required parent element

○Elements with the `role=text` attribute do not have focusable descendents.

○ARIA toggle fields have accessible names

○ARIA `tooltip` elements have accessible names

○ARIA `treeitem` elements have accessible names

○The page contains a heading, skip link, or landmark region

○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.

○Definition list items are wrapped in `<dl>` elements

○ARIA IDs are unique

○No form fields have multiple labels

○`<frame>` or `<iframe>` elements have a title

○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.

○Input buttons have discernible text.

○`<input type="image">` elements have `[alt]` text

○Form elements have associated labels

○The document does not use `<meta http-equiv="refresh">`

○`<object>` elements have alternate text

○Select elements have associated label elements.

○Skip links are focusable.

○No element has a `[tabindex]` value greater than 0

○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.

○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.

○`[lang]` attributes have a valid value

○`<video>` elements contain a `<track>` element with `[kind="captions"]`

○Tables have different content in the summary attribute and `<caption>`.

○All heading elements contain content.

○Uses ARIA roles only on compatible elements

○Image elements do not have `[alt]` attributes that are redundant text.

○Identical links have the same purpose.

○Elements with visible text labels have matching accessible names.

○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.

○`<td>` elements in a large `<table>` have one or more table headers.

Best Practices

General

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

Source	Description
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #423; visit https://reactjs.org/docs/error-decoder.html?invariant=423 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241140) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at bc (https://jestjs.io/assets/js/main.17432a57.js:2:228940) at gc (https://jestjs.io/assets/js/main.17432a57.js:2:228803) at ac (https://jestjs.io/assets/js/main.17432a57.js:2:225638) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224193) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]

●Uses HTTPS

●Avoids deprecated APIs

●Avoids third-party cookies

●Allows users to paste into input fields

●Avoids requesting the geolocation permission on page load

●Avoids requesting the notification permission on page load

●Displays images with correct aspect ratio

●Serves images with appropriate resolution

●Page has the HTML doctype

●Properly defines charset

●No issues in the `Issues` panel in Chrome Devtools

●Ensure CSP is effective against XSS attacks

●Use a strong HSTS policy

●Ensure proper origin isolation with COOP

●Mitigate clickjacking with XFO or CSP

●Mitigate DOM-based XSS with Trusted Types

●Page has valid source maps

○Redirects HTTP traffic to HTTPS

○Detected JavaScript libraries

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

Content Best Practices

Meta descriptions may be included in search results to concisely summarize page content. Learn more about the meta description.

Format your HTML in a way that enables crawlers to better understand your app’s content.

Crawling and Indexing

Search engines may use `href` attributes on links to crawl websites. Ensure that the `href` attribute of anchor elements links to an appropriate destination, so more pages of the site can be discovered. Learn how to make links crawlable

Uncrawlable Link
toBe `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toBeCloseTo `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toEqual `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toStrictEqual `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toHaveProperty `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toMatchSnapshot `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toThrowError `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`

To appear in search results, crawlers need access to your app.

○Structured data is valid

●Page isn’t blocked from indexing

●Document has a `<title>` element

●Page has successful HTTP status code

●Links have descriptive text

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

●Document has a valid `rel=canonical`

○robots.txt is valid

Lighthouse Scores

Industry-standard audits powered by Google Lighthouse. — Desktop

Performance

Accessibility

Best Practices

SEO

Core Web Vitals

Key metrics that affect user experience. — Desktop

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

314 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

1.35 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

30 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.000

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

768 ms

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

1.54 s

Detailed Report

Audit breakdown by category with detailed findings.

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Request	Cache TTL	Transfer Size
jestjs.io/img/content/feature-fast.png	14400.0 s	308.2 KiB
jestjs.io/img/content/feature-coverage.png	14400.0 s	203.5 KiB
jestjs.io/img/content/matchers/toBe.png	14400.0 s	188.5 KiB
jestjs.io/img/content/feature-mocking.png	14400.0 s	188.3 KiB
jestjs.io/assets/js/main.17432a57.js	14400.0 s	140.4 KiB
jestjs.io/img/logos/instagram.png	14400.0 s	55.4 KiB
jestjs.io/img/logos/spotify.png	14400.0 s	39.0 KiB
jestjs.io/assets/js/8155.4644b154.js	14400.0 s	33.0 KiB
jestjs.io/img/logos/airbnb.png	14400.0 s	32.0 KiB
jestjs.io/assets/css/styles.a07fbb26.css	14400.0 s	27.6 KiB
www.google-analytics.com/analytics.js	7200.0 s	20.9 KiB
jestjs.io/img/logos/nyt.png	14400.0 s	10.7 KiB
i.ytimg.com/vi/cAKYQpTC7MA/hqdefault.jpg	7200.0 s	7.8 KiB
images.opencollective.com/datadog/5301801/logo.png	86400.0 s	13.8 KiB
jestjs.io/assets/js/1646.9c736360.js	14400.0 s	7.4 KiB
jestjs.io/assets/js/c4f5d8e4.f64f7276.js	14400.0 s	6.3 KiB
jestjs.io/assets/js/runtime~main.ffe131c7.js	14400.0 s	5.6 KiB
images.opencollective.com/airbnb/d327d66/logo.png	86400.0 s	7.9 KiB
jestjs.io/img/logos/facebook.png	14400.0 s	4.1 KiB
images.opencollective.com/principal/431e690/logo.png	86400.0 s	6.3 KiB
jestjs.io/img/openjs_foundation-logo-horizontal-color-dark_background.svg	14400.0 s	2.5 KiB
jestjs.io/assets/js/3048.004dfdb5.js	14400.0 s	2.3 KiB
jestjs.io/img/logos/twitter.png	14400.0 s	1.8 KiB
jestjs.io/img/logos/thordata.svg	14400.0 s	1.4 KiB
jestjs.io/assets/js/a7456010.2a75c070.js	14400.0 s	322 B

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

	URL	Resource Size	Est Savings
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`	jestjs.io/img/content/feature-fast.png	307.7 KiB	285.1 KiB
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`	jestjs.io/img/content/feature-coverage.png	203.1 KiB	188.2 KiB
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`	jestjs.io/img/content/matchers/toBe.png	188.2 KiB	174.3 KiB
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`	jestjs.io/img/content/feature-mocking.png	187.9 KiB	174.1 KiB
Instagram `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/instagram.png	55.2 KiB	54.3 KiB
Spotify `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/spotify.png	38.8 KiB	37.9 KiB
Airbnb `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/airbnb.png	31.8 KiB	31.3 KiB
Datadog's avatar `div.opencollective > div.opencollective-avatars > a.sponsor-item > img.sponsor-avatar`	images.opencollective.com/datadog/5301801/logo.png	13.2 KiB	12.4 KiB
The New York Times `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/nyt.png	10.6 KiB	9.9 KiB
Airbnb's avatar `div.opencollective > div.opencollective-avatars > a.sponsor-item > img.sponsor-avatar`	images.opencollective.com/airbnb/d327d66/logo.png	7.2 KiB	6.4 KiB

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

More than 4 preconnect connections were found. These should be used sparingly and only to the most important origins.

title: Preconnected origins

description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.

title: Preconnect candidates

value: No additional origins are good candidates for preconnecting

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

URL	Transfer Size	Duration
jestjs.io/assets/css/styles.a07fbb26.css	27.6 KiB	80 ms

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

Diagnostics

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Estimated savings: 0.0 ms 17.9 KiB

URL	Transfer Size	Est Savings
jestjs.io/assets/css/styles.a07fbb26.css	27.5 KiB	17.9 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Estimated savings: 0.0 ms 159.7 KiB

URL	Transfer Size	Est Savings
www.googletagmanager.com/gtag/js?id=G-9V0LCYENMT&cx=c&gtm=4e6411	144.3 KiB	62.7 KiB
www.googletagmanager.com/gtag/js?id=UA-44373548-17	123.4 KiB	62.6 KiB
jestjs.io/assets/js/main.17432a57.js	140.3 KiB	34.4 KiB

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

	URL
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`	jestjs.io/img/content/feature-fast.png
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`	jestjs.io/img/content/feature-coverage.png
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`	jestjs.io/img/content/feature-mocking.png
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`	jestjs.io/img/content/matchers/toBe.png
Airbnb `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/airbnb.png
Facebook `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/facebook.png
Instagram `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/instagram.png
The New York Times `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/nyt.png
Spotify `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/spotify.png
OpenJS Foundation Logo `div.footer__bottom > div.margin-bottom--sm > a.footerLogoLink_tutC > img.footer__logo`	jestjs.io/img/openjs_foundation-logo-horizontal-color-dark_background.svg
Twitter `div.blockContent > div.gridBlockV1 > a.logo-item > img`	jestjs.io/img/logos/twitter.png

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Max Potential First Input Delay 100 ms

●Time to Interactive 1.5 s

●Layout shift culprits

●Document request latency

●Optimize DOM size

●Font display

●Forced reflow

●LCP breakdown

●Modern HTTP

●Optimize viewport for mobile

●Minify CSS

●Minify JavaScript

●Avoids enormous network payloads Total size was 1,727 KiB

●User Timing marks and measures 5 user timings

●JavaScript execution time 0.5 s

●Minimizes main-thread work 1.1 s

●Avoid long main-thread tasks 3 long tasks found

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 20 ms

●Server Backend Latencies 30 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Avoid multiple page redirects

●Initial server response time was short Root document took 20 ms

●Avoid large layout shifts 1 layout shift found

○INP breakdown

○LCP request discovery

○Avoid non-composited animations

Accessibility

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Failing Elements
JEST `div.navbar__inner > div.theme-layout-navbar-left > a.navbar__brand > b.navbar__title`
Search `div.navbarSearchContainer_bzqh > button.DocSearch > span.DocSearch-Button-Container > span.DocSearch-Button-Placeholder`
Follow @jestjs_ `div.wrapperV1 > div.jest-hero-interactive > div.socialLinks_AWWq > a.twitter-follow-button_xhwJ`
PASS `div.jest-card-hitslop > div.jest-card > div.jest-card-front > div.jest-card-label`
PASS `div.jest-card-hitslop > div.jest-card > div.jest-card-front > div.jest-card-label`
JEST `div.jest-card-hitslop > div.jest-card > div.jest-card-front > div.jest-card-label`
PASS `div.jest-card-hitslop > div.jest-card > div.jest-card-front > div.jest-card-label`
zero config `h2 > div > span > p`
snapshots `h2 > div > span > p`
isolated `h2 > div > span > p`
great api `h2 > div > span > p`
FAST AND SAFE `h2 > div > span > p`
--coverage `span > p > a > code`
Mock Functions `div > span > p > a`
toBeCloseTo `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toEqual `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toStrictEqual `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toHaveProperty `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toMatchSnapshot `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toThrowError `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
PHILOSOPHY `div.wrapperV1 > div.blockElement > div.blockContent > h2`
Jest and Delightful JavaScript Testing `div > span > p > a`
Building High-Quality JavaScript Tools `div > span > p > a`
Jest as a Platform `div > span > p > a`
OPEN COLLECTIVE `div.wrapperV1 > div.yellow > div.blockContent > h2`
gold sponsors `div.yellow > div.blockContent > div.opencollective > h3`
featured sponsors `div.yellow > div.blockContent > div.opencollective > h3`
Join 600+ donors `div.blockContent > div.opencollective > p > a`
opencollective.com `div.blockContent > div.opencollective > p > a`
WHO USES JEST? `div.wrapperV1 > div.yellow > div.blockContent > h2`
100m+ million `div > span > p > a`
15,000,000 `div > span > p > a`
OpenJS Foundation `div.footer__bottom > div.footer__copyright > p > a`
OpenJS Foundation `div.footer__bottom > div.footer__copyright > p > a`
OpenJS Foundation `div.footer__bottom > div.footer__copyright > p > a`
Trademark Policy `div.footer__bottom > div.footer__copyright > p > a`
Trademark List `div.footer__bottom > div.footer__copyright > p > a`
list of OpenJS Foundation trademarks `div.footer__bottom > div.footer__copyright > p > a`
The OpenJS Foundation `div.footer__bottom > div.footer__copyright > p > a`
Terms of Use `div.footer__bottom > div.footer__copyright > p > a`
Privacy Policy `div.footer__bottom > div.footer__copyright > p > a`
Bylaws `div.footer__bottom > div.footer__copyright > p > a`
Code of Conduct `div.footer__bottom > div.footer__copyright > p > a`
Trademark Policy `div.footer__bottom > div.footer__copyright > p > a`
Trademark List `div.footer__bottom > div.footer__copyright > p > a`
Cookie Policy `div.footer__bottom > div.footer__copyright > p > a`

Low-contrast text is difficult or impossible for many users to read. Link text that is discernible improves the experience for users with low vision. Learn how to make links distinguishable.

Failing Elements
OpenJS Foundation `div.footer__bottom > div.footer__copyright > p > a`
OpenJS Foundation `div.footer__bottom > div.footer__copyright > p > a`
OpenJS Foundation `div.footer__bottom > div.footer__copyright > p > a`
Trademark Policy `div.footer__bottom > div.footer__copyright > p > a`
Trademark List `div.footer__bottom > div.footer__copyright > p > a`
list of OpenJS Foundation trademarks `div.footer__bottom > div.footer__copyright > p > a`

These are opportunities to improve the legibility of your content.

Names and labels

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Failing Elements
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Best practices

One main landmark helps screen reader users navigate a web page. Learn more about landmarks.

Failing Elements
html.plugin-pages `html.plugin-pages`

These items highlight common accessibility best practices.

○Interactive controls are keyboard focusable

○Interactive elements indicate their purpose and state

○The page has a logical tab order

○Visual order on the page follows DOM order

○User focus is not accidentally trapped in a region

○The user's focus is directed to new content added to the page

○HTML5 landmark elements are used to improve navigation

○Offscreen content is hidden from assistive technology

○Custom controls have associated labels

○Custom controls have ARIA roles

●`[aria-*]` attributes match their roles

●`[aria-hidden="true"]` is not present on the document `<body>`

●`[role]`s have all required `[aria-*]` attributes

●`[role]` values are valid

●`[aria-*]` attributes have valid values

●`[aria-*]` attributes are valid and not misspelled

●Buttons have an accessible name

●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.

●ARIA attributes are used as specified for the element's role

●`[aria-hidden="true"]` elements do not contain focusable descendents

●Elements use only permitted ARIA attributes

●Document has a `<title>` element

●`<html>` element has a `[lang]` attribute

●`<html>` element has a valid value for its `[lang]` attribute

●Links have a discernible name

●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).

●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements

●Touch targets have sufficient size and spacing.

●Heading elements appear in a sequentially-descending order

●Deprecated ARIA roles were not used

●Elements with visible text labels have matching accessible names.

○`[accesskey]` values are unique

○`button`, `link`, and `menuitem` elements have accessible names

○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.

○ARIA input fields have accessible names

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.

○`[role]`s are contained by their required parent element

○Elements with the `role=text` attribute do not have focusable descendents.

○ARIA toggle fields have accessible names

○ARIA `tooltip` elements have accessible names

○ARIA `treeitem` elements have accessible names

○The page contains a heading, skip link, or landmark region

○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.

○Definition list items are wrapped in `<dl>` elements

○ARIA IDs are unique

○No form fields have multiple labels

○`<frame>` or `<iframe>` elements have a title

○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.

○Input buttons have discernible text.

○`<input type="image">` elements have `[alt]` text

○Form elements have associated labels

○The document does not use `<meta http-equiv="refresh">`

○`<object>` elements have alternate text

○Select elements have associated label elements.

○Skip links are focusable.

○No element has a `[tabindex]` value greater than 0

○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.

○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.

○`[lang]` attributes have a valid value

○`<video>` elements contain a `<track>` element with `[kind="captions"]`

○Tables have different content in the summary attribute and `<caption>`.

○All heading elements contain content.

○Uses ARIA roles only on compatible elements

○Image elements do not have `[alt]` attributes that are redundant text.

○Identical links have the same purpose.

○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.

○`<td>` elements in a large `<table>` have one or more table headers.

Best Practices

General

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

Source	Description
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #418; visit https://reactjs.org/docs/error-decoder.html?invariant=418 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at ua (https://jestjs.io/assets/js/main.17432a57.js:2:168788) at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241454) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at yc (https://jestjs.io/assets/js/main.17432a57.js:2:228984) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224065) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]
jestjs.io/assets/js/main.17432a57.js line 1, col 18234	Docusaurus React Root onRecoverableError: Error: Minified React error #423; visit https://reactjs.org/docs/error-decoder.html?invariant=423 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at Sl (https://jestjs.io/assets/js/main.17432a57.js:2:241140) at vc (https://jestjs.io/assets/js/main.17432a57.js:2:229012) at bc (https://jestjs.io/assets/js/main.17432a57.js:2:228940) at gc (https://jestjs.io/assets/js/main.17432a57.js:2:228803) at ac (https://jestjs.io/assets/js/main.17432a57.js:2:225638) at oc (https://jestjs.io/assets/js/main.17432a57.js:2:224193) at k (https://jestjs.io/assets/js/main.17432a57.js:2:400372) at MessagePort.P (https://jestjs.io/assets/js/main.17432a57.js:2:400904) [object Object]

●Uses HTTPS

●Avoids deprecated APIs

●Avoids third-party cookies

●Allows users to paste into input fields

●Avoids requesting the geolocation permission on page load

●Avoids requesting the notification permission on page load

●Displays images with correct aspect ratio

●Serves images with appropriate resolution

●Page has the HTML doctype

●Properly defines charset

●No issues in the `Issues` panel in Chrome Devtools

●Ensure CSP is effective against XSS attacks

●Use a strong HSTS policy

●Ensure proper origin isolation with COOP

●Mitigate clickjacking with XFO or CSP

●Mitigate DOM-based XSS with Trusted Types

●Page has valid source maps

○Redirects HTTP traffic to HTTPS

○Detected JavaScript libraries

SEO

Content Best Practices

Meta descriptions may be included in search results to concisely summarize page content. Learn more about the meta description.

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Failing Elements
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`
div.gridBlockV1 > div.blockElement > div.blockImage > img `div.gridBlockV1 > div.blockElement > div.blockImage > img`

Format your HTML in a way that enables crawlers to better understand your app’s content.

Crawling and Indexing

Uncrawlable Link
toBe `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toBeCloseTo `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toEqual `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toStrictEqual `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toHaveProperty `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toMatchSnapshot `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`
toThrowError `div.blockElement > div.blockContent > p.buttons-wrapper > a.button`

To appear in search results, crawlers need access to your app.

○Structured data is valid

●Page isn’t blocked from indexing

●Document has a `<title>` element

●Page has successful HTTP status code

●Links have descriptive text

●Document has a valid `hreflang`

●Document has a valid `rel=canonical`

○robots.txt is valid

Results for https://jestjs.io

Site Health

Top Priorities (5)

Lighthouse Scores

Core Web Vitals

Detailed Report

Performance

Insights

Diagnostics

Accessibility

Contrast

Best practices

Best Practices

General

SEO

Content Best Practices

Crawling and Indexing

Lighthouse Scores

Core Web Vitals

Detailed Report

Performance

Insights

Diagnostics

Accessibility

Contrast

Names and labels

Best practices

Best Practices

General

SEO

Content Best Practices

Crawling and Indexing

Keyboard Shortcuts