Initial docs for experimental Web Performance APIs

docs/_canary-channel-api-warning.mdx

@@ -0,0 +1,7 @@
+:::important Canary 🧪
+
+**This API is currently only available in React Native’s Canary and Experimental channels.**
+
+[Learn more about React Native’s release channels here.](releases/release-levels)
+
+:::

docs/_experimental-channel-api-warning.mdx

@@ -0,0 +1,9 @@
+:::important Experimental Feature 🧪
+
+**This API is experimental and is not available in a stable version of React Native yet.**
+
+Experimental APIs may contain bugs and are likely to change in a future version of React Native. Don't use them in production.
+
+If you want to try it out, please [enable the Experimental Channel](releases/release-levels) in your app.
+
+:::

docs/global-EventCounts.md

@@ -0,0 +1,10 @@
+---
+id: global-EventCounts
+title: EventCounts 🧪
+---
+
+import CanaryAPIWarning from './\_canary-channel-api-warning.mdx';
+
+<CanaryAPIWarning />
+
+The global [`EventCounts`](https://developer.mozilla.org/en-US/docs/Web/API/EventCounts) class, as defined in Web specifications.

docs/global-PerformanceEntry.md

@@ -0,0 +1,10 @@
+---
+id: global-PerformanceEntry
+title: PerformanceEntry 🧪
+---
+
+import CanaryAPIWarning from './\_canary-channel-api-warning.mdx';
+
+<CanaryAPIWarning />
+
+The global [`PerformanceEntry`](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceEntry) class, as defined in Web specifications.

docs/global-PerformanceEventTiming.md

@@ -0,0 +1,14 @@
+---
+id: global-PerformanceEventTiming
+title: PerformanceEventTiming 🧪
+---
+
+import CanaryAPIWarning from './\_canary-channel-api-warning.mdx';
+
+<CanaryAPIWarning />
+
+The global [`PerformanceEventTiming`](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceEventTiming) class, as defined in Web specifications.
+
+:::info Partial support
+The `cancelable` and `target` properties are not supported yet.
+:::

docs/global-PerformanceLongTaskTiming.md

@@ -0,0 +1,14 @@
+---
+id: global-PerformanceLongTaskTiming
+title: PerformanceLongTaskTiming 🧪
+---
+
+import CanaryAPIWarning from './\_canary-channel-api-warning.mdx';
+
+<CanaryAPIWarning />
+
+The global [`PerformanceLongTaskTiming`](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceLongTaskTiming) class, as defined in Web specifications.
+
+:::info Partial support
+The value for the `attribution` property is always an empty array.
+:::

docs/global-PerformanceMark.md

@@ -0,0 +1,10 @@
+---
+id: global-PerformanceMark
+title: PerformanceMark 🧪
+---
+
+import CanaryAPIWarning from './\_canary-channel-api-warning.mdx';
+
+<CanaryAPIWarning />
+
+The global [`PerformanceMark`](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceMark) class, as defined in Web specifications.

docs/global-PerformanceMeasure.md

@@ -0,0 +1,10 @@
+---
+id: global-PerformanceMeasure
+title: PerformanceMeasure 🧪
+---
+
+import CanaryAPIWarning from './\_canary-channel-api-warning.mdx';
+
+<CanaryAPIWarning />
+
+The global [`PerformanceMeasure`](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceMeasure) class, as defined in Web specifications.

docs/global-PerformanceObserver.md

@@ -0,0 +1,62 @@
+---
+id: global-PerformanceObserver
+title: PerformanceObserver 🧪
+---
+
+import CanaryAPIWarning from './\_canary-channel-api-warning.mdx';
+
+<CanaryAPIWarning />
+
+The global [`PerformanceObserver`](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceObserver) class, as defined in Web specifications.
+
+## Example
+
+```ts
+const observer = new PerformanceObserver(
+  (list, observer, options) => {
+    for (const entry of list.getEntries()) {
+      console.log(
+        'Received entry with type',
+        entry.entryType,
+        'and name',
+        entry.name,
+        'that started at',
+        entry.startTime,
+        'and took',
+        entry.duration,
+        'ms',
+      );
+    }
+  },
+);
+
+observer.observe({entryTypes: ['mark', 'measure']});
+```
+
+---
+
+# Reference
+
+## Constructor
+
+### `PerformanceObserver()`
+
+See [documentation in MDN](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceObserver/PerformanceObserver).
+
+## Static properties
+
+### `supportedEntryTypes`
+
+See [documentation in MDN](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceObserver/supportedEntryTypes).
+
+Returns `['mark', 'measure', 'event', 'longtask']`.
+
+## Instance methods
+
+### `observe()`
+
+See [documentation in MDN](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceObserver/observe).
+
+### `disconnect()`
+
+See [documentation in MDN](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceObserver/disconnect).

docs/global-PerformanceObserverEntryList.md

@@ -0,0 +1,10 @@
+---
+id: global-PerformanceObserverEntryList
+title: PerformanceObserverEntryList 🧪
+---
+
+import CanaryAPIWarning from './\_canary-channel-api-warning.mdx';
+
+<CanaryAPIWarning />
+
+The global [`PerformanceObserverEntryList`](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceObserverEntryList) class, as defined in Web specifications.

docs/global-performance.md

@@ -1,10 +1,91 @@
 ---
 id: global-performance
-title: performance
+title: performance 🧪
 ---
 
-:::warning
-🚧 This page is work in progress, so please refer to the [MDN documentation](https://developer.mozilla.org/en-US/docs/Web/API/performance) for more information.
+import CanaryAPIWarning from './\_canary-channel-api-warning.mdx';
+
+<CanaryAPIWarning />
+
+The global [`performance`](https://developer.mozilla.org/en-US/docs/Web/API/Window/performance) object, as defined in Web specifications.
+
+---
+
+# Reference
+
+## Instance properties
+
+### `eventCounts`
+
+See [documentation in MDN](https://developer.mozilla.org/en-US/docs/Web/API/Performance/eventCounts).
+
+### `memory`
+
+See [documentation in MDN](https://developer.mozilla.org/en-US/docs/Web/API/Performance/memory).
+
+### `rnStartupTiming` ⚠️
+
+:::warning Non-standard
+This is a React Native specific extension.
+:::
+
+Provides information about the startup time of the application.
+
+```ts
+get rnStartupTiming(): ReactNativeStartupTiming;
+```
+
+The `ReactNativeStartupTiming` interface provides the following fields:
+
+| Name                                     | Type           | Description                                               |
+| ---------------------------------------- | -------------- | --------------------------------------------------------- |
+| `startTime`                              | number \| void | When the application startup was started.                 |
+| `initializeRuntimeStart`                 | number \| void | When the React Native runtime initialization was started. |
+| `executeJavaScriptBundleEntryPointStart` | number \| void | When the execution of the application bundle was started. |
+| `endTime`                                | number \| void | When the React Native runtime was fully initialized.      |
+
+### `timeOrigin`
+
+:::info Partial support
+Provides the number of milliseconds from the UNIX epoch until system boot, instead of the number of milliseconds from the UNIX epoch until app startup.
+:::
+
+See [documentation in MDN](https://developer.mozilla.org/en-US/docs/Web/API/Performance/timeOrigin).
+
+## Instance methods
+
+### `clearMarks()`
+
+See [documentation in MDN](https://developer.mozilla.org/en-US/docs/Web/API/Performance/clearMarks).
+
+### `clearMeasures()`
+
+See [documentation in MDN](https://developer.mozilla.org/en-US/docs/Web/API/Performance/clearMeasures).
+
+### `getEntries()`
+
+See [documentation in MDN](https://developer.mozilla.org/en-US/docs/Web/API/Performance/getEntries).
+
+### `getEntriesByName()`
+
+See [documentation in MDN](https://developer.mozilla.org/en-US/docs/Web/API/Performance/getEntriesByName).
+
+### `getEntriesByType()`
+
+See [documentation in MDN](https://developer.mozilla.org/en-US/docs/Web/API/Performance/getEntriesByType).
+
+### `mark()`
+
+See [documentation in MDN](https://developer.mozilla.org/en-US/docs/Web/API/Performance/mark).
+
+### `measure()`
+
+See [documentation in MDN](https://developer.mozilla.org/en-US/docs/Web/API/Performance/measure).
+
+### `now()`
+
+:::info Partial support
+Provides the number of milliseconds from system boot, instead of the number of milliseconds from app startup.
 :::
 
-The global `performance` object, as defined in Web specifications.
+See [documentation in MDN](https://developer.mozilla.org/en-US/docs/Web/API/Performance/now).

website/sidebars.ts

@@ -240,6 +240,7 @@ export default {
           'global-clearInterval',
           'global-clearTimeout',
           'global-console',
+          'global-EventCounts',
           'global-fetch',
           'global-File',
           'global-FileReader',
@@ -248,6 +249,13 @@ export default {
           'global-Headers',
           'global-navigator',
           'global-performance',
+          'global-PerformanceEntry',
+          'global-PerformanceEventTiming',
+          'global-PerformanceLongTaskTiming',
+          'global-PerformanceMark',
+          'global-PerformanceMeasure',
+          'global-PerformanceObserver',
+          'global-PerformanceObserverEntryList',
           'global-process',
           'global-queueMicrotask',
           'global-Request',