core: move no-unload-listeners to perf category #13497
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brendankenny
requested review from
connorjclark
and removed request for
a team
brendankenny
commented
Dec 14, 2021
| @@ -15,7 +15,7 @@ const UIStrings = { | |||
| /** Descriptive title of a Lighthouse audit that checks if a web page has 'unload' event listeners and finds that it is using them. */ | |||
| failureTitle: 'Registers an `unload` listener', | |||
| /** Description of a Lighthouse audit that tells the user why pages should not use the 'unload' event. This is displayed after a user expands the section to see more. 'Learn More' becomes link text to additional documentation. */ | |||
| description: 'The `unload` event does not fire reliably and listening for it can prevent browser optimizations like the Back-Forward Cache. Consider using the `pagehide` or `visibilitychange` events instead. [Learn more](https://developers.google.com/web/updates/2018/07/page-lifecycle-api#the-unload-event)', | |||
| description: 'The `unload` event does not fire reliably and listening for it can prevent browser optimizations like the Back-Forward Cache. Use `pagehide` or `visibilitychange` events instead. [Learn more](https://web.dev/bfcache/#never-use-the-unload-event)', | |||
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stronger-worded advice because from experiments the bfcache team did, disabling/ignoring unload handlers in some circumstances (like Safari sometimes does) probably won't be an option for Chrome due to web breakage.
connorjclark
approved these changes
Dec 14, 2021
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The Chrome bfcache team has determined that unload handlers are the top developer-controllable reason pages aren't able to use the bfcache. The bfcache is by far the fastest way to load a page if navigating by history, so it makes sense to have the audit in the perf category. We discussed this back in #11085 (comment) but punted on the question at the time.
Having it in the perf category also means it will show up in the PSI report, which will reach that many more developers.
Also updates the learn more link to the newer https://web.dev/bfcache article.