doc: improve perf_hooks docs

PR-URL: #36909 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
nodejs · Jan 21, 2021 · 8cf280d · 8cf280d
1 parent 889654d
commit 8cf280d
Showing 1 changed file with 104 additions and 0 deletions.
diff --git a/doc/api/perf_hooks.md b/doc/api/perf_hooks.md
@@ -523,6 +523,38 @@ added: v8.5.0
 Returns a list of `PerformanceEntry` objects in chronological order
 with respect to `performanceEntry.startTime`.
 
+```js
+const {
+  performance,
+  PerformanceObserver
+} = require('perf_hooks');
+
+const obs = new PerformanceObserver((perfObserverList, observer) => {
+  console.log(perfObserverList.getEntries());
+  /**
+   * [
+   *   PerformanceEntry {
+   *     name: 'test',
+   *     entryType: 'mark',
+   *     startTime: 81.465639,
+   *     duration: 0
+   *   },
+   *   PerformanceEntry {
+   *     name: 'meow',
+   *     entryType: 'mark',
+   *     startTime: 81.860064,
+   *     duration: 0
+   *   }
+   * ]
+   */
+  observer.disconnect();
+});
+obs.observe({ entryTypes: ['mark'], buffered: true });
+
+performance.mark('test');
+performance.mark('meow');
+```
+
 ### `performanceObserverEntryList.getEntriesByName(name[, type])`
 <!-- YAML
 added: v8.5.0
@@ -537,6 +569,46 @@ with respect to `performanceEntry.startTime` whose `performanceEntry.name` is
 equal to `name`, and optionally, whose `performanceEntry.entryType` is equal to
 `type`.
 
+```js
+const {
+  performance,
+  PerformanceObserver
+} = require('perf_hooks');
+
+const obs = new PerformanceObserver((perfObserverList, observer) => {
+  console.log(perfObserverList.getEntriesByName('meow'));
+  /**
+   * [
+   *   PerformanceEntry {
+   *     name: 'meow',
+   *     entryType: 'mark',
+   *     startTime: 98.545991,
+   *     duration: 0
+   *   }
+   * ]
+   */
+  console.log(perfObserverList.getEntriesByName('nope')); // []
+
+  console.log(perfObserverList.getEntriesByName('test', 'mark'));
+  /**
+   * [
+   *   PerformanceEntry {
+   *     name: 'test',
+   *     entryType: 'mark',
+   *     startTime: 63.518931,
+   *     duration: 0
+   *   }
+   * ]
+   */
+  console.log(perfObserverList.getEntriesByName('test', 'measure')); // []
+  observer.disconnect();
+});
+obs.observe({ entryTypes: ['mark', 'measure'], buffered: true });
+
+performance.mark('test');
+performance.mark('meow');
+```
+
 ### `performanceObserverEntryList.getEntriesByType(type)`
 <!-- YAML
 added: v8.5.0
@@ -549,6 +621,38 @@ Returns a list of `PerformanceEntry` objects in chronological order
 with respect to `performanceEntry.startTime` whose `performanceEntry.entryType`
 is equal to `type`.
 
+```js
+const {
+  performance,
+  PerformanceObserver
+} = require('perf_hooks');
+
+const obs = new PerformanceObserver((perfObserverList, observer) => {
+  console.log(perfObserverList.getEntriesByType('mark'));
+  /**
+   * [
+   *   PerformanceEntry {
+   *     name: 'test',
+   *     entryType: 'mark',
+   *     startTime: 55.897834,
+   *     duration: 0
+   *   },
+   *   PerformanceEntry {
+   *     name: 'meow',
+   *     entryType: 'mark',
+   *     startTime: 56.350146,
+   *     duration: 0
+   *   }
+   * ]
+   */
+  observer.disconnect();
+});
+obs.observe({ entryTypes: ['mark'], buffered: true });
+
+performance.mark('test');
+performance.mark('meow');
+```
+
 ## `perf_hooks.monitorEventLoopDelay([options])`
 <!-- YAML
 added: v11.10.0