new PerformanceObserver(callback)

• callback <Function>

  • list <PerformanceObserverEntryList>

  • observer <PerformanceObserver>

当新的 PerformanceEntry 实例被添加到性能时间线时，则 PerformanceObserver 对象会提供通知。

¥PerformanceObserver objects provide notifications when new PerformanceEntry instances have been added to the Performance Timeline.

import { performance, PerformanceObserver } from 'node:perf_hooks';

const obs = new PerformanceObserver((list, observer) => {
  console.log(list.getEntries());

  performance.clearMarks();
  performance.clearMeasures();
  observer.disconnect();
});
obs.observe({ entryTypes: ['mark'], buffered: true });

performance.mark('test');const {
  performance,
  PerformanceObserver,
} = require('node:perf_hooks');

const obs = new PerformanceObserver((list, observer) => {
  console.log(list.getEntries());

  performance.clearMarks();
  performance.clearMeasures();
  observer.disconnect();
});
obs.observe({ entryTypes: ['mark'], buffered: true });

performance.mark('test');拷贝

因为 PerformanceObserver 实例引入了它们自己的额外性能开销，实例不应无限期地订阅通知。一旦不再需要监视器，则用户应立即断开监视器的连接。

¥Because PerformanceObserver instances introduce their own additional performance overhead, instances should not be left subscribed to notifications indefinitely. Users should disconnect observers as soon as they are no longer needed.

当 PerformanceObserver 接收到有关新的 PerformanceEntry 实例的通知时，则会调用 callback。回调接收到 PerformanceObserverEntryList 实例和对 PerformanceObserver 的引用。

¥The callback is invoked when a PerformanceObserver is notified about new PerformanceEntry instances. The callback receives a PerformanceObserverEntryList instance and a reference to the PerformanceObserver.