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Defer CLS logic until after onFCP callback #297

Merged
merged 2 commits into from
Jan 9, 2023
Merged

Defer CLS logic until after onFCP callback #297

merged 2 commits into from
Jan 9, 2023

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philipwalton
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This PR fixes #180 by removing some of the logic that would listen and keep track of whether or not FCP had fired, and instead just wraps all of the onCLS() logic inside of an onFCP() call (and ensuring the logic only runs the first time onFCP() is invoked).

The "ensuring the logic only runs the first time onFCP() is invoked" bit is accomplished by introducing a new runOnce() utility function, and I took this opportunity to refactor some of the other code to make use of that. The end result was a little bit of byte savings, so it was worth it.

Also, #180 caught a bug in the library where, if the library was lazy-loaded, CLS wouldn't properly be reported when reportAllChanges was true. I realized there were no tests to ensure things work when the library is lazy-loaded, so I added some, which also required refactoring some of the testing logic.

Lastly, this PR also updates a bit of the formatting style (continuing what was done in #288) since some of that was auto-formatting unrelated files anyway (not sure why, but seems to be fine now).

tunetheweb
tunetheweb approved these changes Jan 9, 2023
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LGTM but have some comments (mostly for my own curiosity).

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@philipwalton philipwalton merged commit e5e4a6d into main Jan 9, 2023
@philipwalton philipwalton deleted the late-execution branch January 9, 2023 22:05
@Kobe
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Kobe commented Jan 31, 2023

@philipwalton @tunetheweb does this adjustment have an impact on concrete CLS numbers?

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It does not, other than cases affected by the bug outlined in this comment: #180 (comment)

@lisr lisr mentioned this pull request May 24, 2023
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@sethulakshmi-pm sethulakshmi-pm mentioned this pull request Oct 10, 2023
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zemnmez-renovate-bot added a commit to zemn-me/monorepo that referenced this pull request Oct 5, 2024
@zemnmez-renovate-bot
fix(deps): update dependency web-vitals to v4
b07a342 
##### [`v4.2.3](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v423-2024-08-06)

-   Fix missing LoAF entries in INP attribution ([#512](GoogleChrome/web-vitals#512))
##### [`v4.2.2](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v422-2024-07-17)

-   Fix interaction count after bfcache restore ([#505](GoogleChrome/web-vitals#505))
##### [`v4.2.1](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v421-2024-06-30)

-   Fix compatibility issues with TypeScript v5.5 ([#497](GoogleChrome/web-vitals#497))
##### [`v4.2.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v420-2024-06-20)

-   Refactor INP attribution code to fix errors on Windows 10 ([#495](GoogleChrome/web-vitals#495))
##### [`v4.1.1](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v411-2024-06-10)

-   Fix pending LoAF cleanup logic ([#493](GoogleChrome/web-vitals#493))
##### [`v4.1.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v410-2024-06-06)

-   Move the support check to the top of the onINP() function ([#490](GoogleChrome/web-vitals#490))
-   Fix missing LoAF attribution when entries are dispatched before event entries ([#487](GoogleChrome/web-vitals#487))
##### [`v4.0.1](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v401-2024-05-21)

-   Add the `ReportCallback` type back but deprecate it ([#483](GoogleChrome/web-vitals#483))
##### [`v4.0.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v400-2024-05-13)

-   **\[BREAKING]** Update types to support more generic usage ([#471](GoogleChrome/web-vitals#471))
-   **\[BREAKING]** Split `waitingDuration` to make it easier to understand redirect delays ([#458](GoogleChrome/web-vitals#458))
-   **\[BREAKING]** Rename `TTFBAttribution` fields from `*Time` to `*Duration` ([#453](GoogleChrome/web-vitals#453))
-   **\[BREAKING]** Rename `resourceLoadTime` to `resourceLoadDuration` in LCP attribution ([#450](GoogleChrome/web-vitals#450))
-   **\[BREAKING]** Add INP breakdown timings and LoAF attribution ([#442](GoogleChrome/web-vitals#442))
-   **\[BREAKING]** Deprecate `onFID()` and remove previously deprecated APIs ([#435](GoogleChrome/web-vitals#435))
-   Expose the target element in INP attribution ([#479](GoogleChrome/web-vitals#479))
-   Save INP target after interactions to reduce null values when removed from the DOM ([#477](GoogleChrome/web-vitals#477))
-   Cap TTFB in attribution ([#440](GoogleChrome/web-vitals#440))
-   Fix `reportAllChanges` behavior for LCP when library is loaded late ([#468](GoogleChrome/web-vitals#468))
##### [`v3.5.2](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v352-2024-01-25)

-   Pick the first non-null `target` for INP attribution ([#421](GoogleChrome/web-vitals#421))
##### [`v3.5.1](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v351-2023-12-27)

-   Add extra guard for `PerformanceEventTiming` not existing ([#403](GoogleChrome/web-vitals#403))
##### [`v3.5.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v350-2023-09-28)

-   Run `onLCP` callback in separate task ([#386](GoogleChrome/web-vitals#386))
-   Fix INP durationThreshold bug when set to 0 ([#372](GoogleChrome/web-vitals#372))
-   Prevent FID entries being emitted as INP for non-supporting browsers ([#368](GoogleChrome/web-vitals#368))
##### [`v3.4.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v340-2023-07-11)

-   Make `bindReporter` generic over metric type ([#359](GoogleChrome/web-vitals#359))
-   Update INP status in README ([#362](GoogleChrome/web-vitals#362))
-   Fix Metric types for better TypeScript support ([#356](GoogleChrome/web-vitals#356))
-   Fix selector for SVGs for attribution build ([#354](GoogleChrome/web-vitals#354))
##### [`v3.3.2](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v332-2023-05-29)

-   Fix attribution types ([#348](GoogleChrome/web-vitals#348))
-   Safe access navigation entry type ([#290](GoogleChrome/web-vitals#290))
##### [`v3.3.1](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v331-2023-04-04)

-   Export metric rating thresholds in attribution build as well.
##### [`v3.3.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v330-2023-03-09)

-   Export metric rating thresholds, add explicit `MetricRatingThresholds` type ([#323](GoogleChrome/web-vitals#323))
-   Trim classname selector ([#328](GoogleChrome/web-vitals#328))
-   Add link to CrUX versus RUM blog post ([#327](GoogleChrome/web-vitals#327))
-   Prevent LCP being reported for hidden prerendered pages ([#326](GoogleChrome/web-vitals#326))
-   Add Server Timing information to docs ([#324](GoogleChrome/web-vitals#324))
-   Fix link in `onINP()` thresholds comment ([#318](GoogleChrome/web-vitals#318))
-   Update web.dev link for `onINP()` ([#307](GoogleChrome/web-vitals#307))
-   Add a note about when to load the library ([#305](GoogleChrome/web-vitals#305))
##### [`v3.1.1](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v311-2023-01-10)

-   Defer CLS logic until after `onFCP()` callback ([#297](GoogleChrome/web-vitals#297))
##### [`v3.1.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v310-2022-11-15)

-   Add support for `'restore'` as a `navigationType` ([#284](GoogleChrome/web-vitals#284))
-   Report initial CLS value when `reportAllChanges` is true ([#283](GoogleChrome/web-vitals#283))
-   Defer all observers until after activation ([#282](GoogleChrome/web-vitals#282))
-   Ignore TTFB for loads where responseStart is zero ([#281](GoogleChrome/web-vitals#281))
-   Defer execution of observer callbacks ([#278](GoogleChrome/web-vitals#278))
##### [`v3.0.4](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v304-2022-10-18)

-   Clamp LCP and FCP to 0 for prerendered pages ([#270](GoogleChrome/web-vitals#270))
##### [`v3.0.3](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v303-2022-10-04)

-   Ensure `attribution` object is always present in attribution build ([#265](GoogleChrome/web-vitals#265))
##### [`v3.0.2](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v302-2022-09-14)

-   Set an explicit unpkg dist file ([#261](GoogleChrome/web-vitals#261))
##### [`v3.0.1](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v301-2022-08-31)

-   Use the cjs extension for all UMD builds ([#257](GoogleChrome/web-vitals#257))
##### [`v3.0.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v300-2022-08-24)

-   **\[BREAKING]** Add a config object param to all metric functions ([#225](GoogleChrome/web-vitals#225))
-   **\[BREAKING]** Report TTFB after a bfcache restore ([#220](GoogleChrome/web-vitals#220))
-   **\[BREAKING]** Only include last LCP entry in metric entries ([#218](GoogleChrome/web-vitals#218))
-   Update the metric ID prefix for v3 ([#251](GoogleChrome/web-vitals#251))
-   Move the Navigation Timing API polyfill to the base+polyfill build ([#248](GoogleChrome/web-vitals#248))
-   Add a metric rating property ([#246](GoogleChrome/web-vitals#246))
-   Add deprecation notices for base+polyfill builds ([#242](GoogleChrome/web-vitals#242))
-   Add a new attribution build for debugging issues in the field ([#237](GoogleChrome/web-vitals#237), [#244](GoogleChrome/web-vitals#244))
-   Add support for prerendered pages ([#233](GoogleChrome/web-vitals#233))
-   Rename the `ReportHandler` type to `ReportCallback`, with alias for back-compat ([#225](GoogleChrome/web-vitals#225), [#227](GoogleChrome/web-vitals#227))
-   Add support for the new INP metric ([#221](GoogleChrome/web-vitals#221), [#232](GoogleChrome/web-vitals#232))
-   Rename `getXXX()` functions to `onXXX()` ([#222](GoogleChrome/web-vitals#222))
-   Add a `navigationType` property to the Metric object ([#219](GoogleChrome/web-vitals#219))
github-merge-queue bot pushed a commit to zemn-me/monorepo that referenced this pull request Oct 5, 2024
@zemnmez-renovate-bot
fix(deps): update dependency web-vitals to v4
f7232d4 
##### [`v4.2.3](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v423-2024-08-06)

-   Fix missing LoAF entries in INP attribution ([#512](GoogleChrome/web-vitals#512))
##### [`v4.2.2](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v422-2024-07-17)

-   Fix interaction count after bfcache restore ([#505](GoogleChrome/web-vitals#505))
##### [`v4.2.1](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v421-2024-06-30)

-   Fix compatibility issues with TypeScript v5.5 ([#497](GoogleChrome/web-vitals#497))
##### [`v4.2.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v420-2024-06-20)

-   Refactor INP attribution code to fix errors on Windows 10 ([#495](GoogleChrome/web-vitals#495))
##### [`v4.1.1](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v411-2024-06-10)

-   Fix pending LoAF cleanup logic ([#493](GoogleChrome/web-vitals#493))
##### [`v4.1.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v410-2024-06-06)

-   Move the support check to the top of the onINP() function ([#490](GoogleChrome/web-vitals#490))
-   Fix missing LoAF attribution when entries are dispatched before event entries ([#487](GoogleChrome/web-vitals#487))
##### [`v4.0.1](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v401-2024-05-21)

-   Add the `ReportCallback` type back but deprecate it ([#483](GoogleChrome/web-vitals#483))
##### [`v4.0.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v400-2024-05-13)

-   **\[BREAKING]** Update types to support more generic usage ([#471](GoogleChrome/web-vitals#471))
-   **\[BREAKING]** Split `waitingDuration` to make it easier to understand redirect delays ([#458](GoogleChrome/web-vitals#458))
-   **\[BREAKING]** Rename `TTFBAttribution` fields from `*Time` to `*Duration` ([#453](GoogleChrome/web-vitals#453))
-   **\[BREAKING]** Rename `resourceLoadTime` to `resourceLoadDuration` in LCP attribution ([#450](GoogleChrome/web-vitals#450))
-   **\[BREAKING]** Add INP breakdown timings and LoAF attribution ([#442](GoogleChrome/web-vitals#442))
-   **\[BREAKING]** Deprecate `onFID()` and remove previously deprecated APIs ([#435](GoogleChrome/web-vitals#435))
-   Expose the target element in INP attribution ([#479](GoogleChrome/web-vitals#479))
-   Save INP target after interactions to reduce null values when removed from the DOM ([#477](GoogleChrome/web-vitals#477))
-   Cap TTFB in attribution ([#440](GoogleChrome/web-vitals#440))
-   Fix `reportAllChanges` behavior for LCP when library is loaded late ([#468](GoogleChrome/web-vitals#468))
##### [`v3.5.2](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v352-2024-01-25)

-   Pick the first non-null `target` for INP attribution ([#421](GoogleChrome/web-vitals#421))
##### [`v3.5.1](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v351-2023-12-27)

-   Add extra guard for `PerformanceEventTiming` not existing ([#403](GoogleChrome/web-vitals#403))
##### [`v3.5.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v350-2023-09-28)

-   Run `onLCP` callback in separate task ([#386](GoogleChrome/web-vitals#386))
-   Fix INP durationThreshold bug when set to 0 ([#372](GoogleChrome/web-vitals#372))
-   Prevent FID entries being emitted as INP for non-supporting browsers ([#368](GoogleChrome/web-vitals#368))
##### [`v3.4.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v340-2023-07-11)

-   Make `bindReporter` generic over metric type ([#359](GoogleChrome/web-vitals#359))
-   Update INP status in README ([#362](GoogleChrome/web-vitals#362))
-   Fix Metric types for better TypeScript support ([#356](GoogleChrome/web-vitals#356))
-   Fix selector for SVGs for attribution build ([#354](GoogleChrome/web-vitals#354))
##### [`v3.3.2](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v332-2023-05-29)

-   Fix attribution types ([#348](GoogleChrome/web-vitals#348))
-   Safe access navigation entry type ([#290](GoogleChrome/web-vitals#290))
##### [`v3.3.1](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v331-2023-04-04)

-   Export metric rating thresholds in attribution build as well.
##### [`v3.3.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v330-2023-03-09)

-   Export metric rating thresholds, add explicit `MetricRatingThresholds` type ([#323](GoogleChrome/web-vitals#323))
-   Trim classname selector ([#328](GoogleChrome/web-vitals#328))
-   Add link to CrUX versus RUM blog post ([#327](GoogleChrome/web-vitals#327))
-   Prevent LCP being reported for hidden prerendered pages ([#326](GoogleChrome/web-vitals#326))
-   Add Server Timing information to docs ([#324](GoogleChrome/web-vitals#324))
-   Fix link in `onINP()` thresholds comment ([#318](GoogleChrome/web-vitals#318))
-   Update web.dev link for `onINP()` ([#307](GoogleChrome/web-vitals#307))
-   Add a note about when to load the library ([#305](GoogleChrome/web-vitals#305))
##### [`v3.1.1](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v311-2023-01-10)

-   Defer CLS logic until after `onFCP()` callback ([#297](GoogleChrome/web-vitals#297))
##### [`v3.1.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v310-2022-11-15)

-   Add support for `'restore'` as a `navigationType` ([#284](GoogleChrome/web-vitals#284))
-   Report initial CLS value when `reportAllChanges` is true ([#283](GoogleChrome/web-vitals#283))
-   Defer all observers until after activation ([#282](GoogleChrome/web-vitals#282))
-   Ignore TTFB for loads where responseStart is zero ([#281](GoogleChrome/web-vitals#281))
-   Defer execution of observer callbacks ([#278](GoogleChrome/web-vitals#278))
##### [`v3.0.4](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v304-2022-10-18)

-   Clamp LCP and FCP to 0 for prerendered pages ([#270](GoogleChrome/web-vitals#270))
##### [`v3.0.3](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v303-2022-10-04)

-   Ensure `attribution` object is always present in attribution build ([#265](GoogleChrome/web-vitals#265))
##### [`v3.0.2](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v302-2022-09-14)

-   Set an explicit unpkg dist file ([#261](GoogleChrome/web-vitals#261))
##### [`v3.0.1](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v301-2022-08-31)

-   Use the cjs extension for all UMD builds ([#257](GoogleChrome/web-vitals#257))
##### [`v3.0.0](https://github.com/GoogleChrome/web-vitals/blob/HEAD/CHANGELOG.md#v300-2022-08-24)

-   **\[BREAKING]** Add a config object param to all metric functions ([#225](GoogleChrome/web-vitals#225))
-   **\[BREAKING]** Report TTFB after a bfcache restore ([#220](GoogleChrome/web-vitals#220))
-   **\[BREAKING]** Only include last LCP entry in metric entries ([#218](GoogleChrome/web-vitals#218))
-   Update the metric ID prefix for v3 ([#251](GoogleChrome/web-vitals#251))
-   Move the Navigation Timing API polyfill to the base+polyfill build ([#248](GoogleChrome/web-vitals#248))
-   Add a metric rating property ([#246](GoogleChrome/web-vitals#246))
-   Add deprecation notices for base+polyfill builds ([#242](GoogleChrome/web-vitals#242))
-   Add a new attribution build for debugging issues in the field ([#237](GoogleChrome/web-vitals#237), [#244](GoogleChrome/web-vitals#244))
-   Add support for prerendered pages ([#233](GoogleChrome/web-vitals#233))
-   Rename the `ReportHandler` type to `ReportCallback`, with alias for back-compat ([#225](GoogleChrome/web-vitals#225), [#227](GoogleChrome/web-vitals#227))
-   Add support for the new INP metric ([#221](GoogleChrome/web-vitals#221), [#232](GoogleChrome/web-vitals#232))
-   Rename `getXXX()` functions to `onXXX()` ([#222](GoogleChrome/web-vitals#222))
-   Add a `navigationType` property to the Metric object ([#219](GoogleChrome/web-vitals#219))
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Successfully merging this pull request may close these issues.

Reporting CLS and LCP in a lab environment using Playwright is flakey / unreliable
3 participants
@philipwalton @Kobe @tunetheweb