PerformanceObserver.prototype.observe - perf_hooks - Node

PerformanceObserver.prototype.observe - perf_hooks - Node documentation

method PerformanceObserver.prototype.observe

Usage in Deno

import { PerformanceObserver } from "node:perf_hooks";



PerformanceObserver.prototype.observe(options: { entryTypes: readonly EntryType[]; buffered?: boolean | undefined;  } | { type: EntryType; buffered?: boolean | undefined;  }): void

Subscribes the PerformanceObserver instance to notifications of new PerformanceEntry instances identified either by options.entryTypes or options.type:

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

const obs = new PerformanceObserver((list, observer) => {
  // Called once asynchronously. `list` contains three items.
});
obs.observe({ type: 'mark' });

for (let n = 0; n < 3; n++)
  performance.mark(`test${n}`);

Parameters



options: { entryTypes: readonly EntryType[]; buffered?: boolean | undefined;  } | { type: EntryType; buffered?: boolean | undefined;  }

Return Type

void