performanceObserver.observe(options)

• options <Object>
  • type <string> 单个 <PerformanceEntry> 类型。 如果已经指定了 entryTypes，则不能给出。
  • entryTypes <string[]> 标识观察者感兴趣的 <PerformanceEntry> 实例类型的字符串数组。 如果未提供，将抛出错误。
  • buffered <boolean> 如果为 true，则使用列表全局 PerformanceEntry 缓冲条目调用观察者回调。 如果为false，则只有在时间点之后创建的 PerformanceEntry 被发送到观察者回调。 默认值: false。

为 <PerformanceObserver> 实例订阅由 options.entryTypes 或 options.type 标识的新 <PerformanceEntry> 实例的通知：

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

const obs = new PerformanceObserver((list, observer) => {
  // 异步调用一次。`list` 包含三个条目。
});
obs.observe({ type: 'mark' });

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

• options <Object>
  • type <string> A single <PerformanceEntry> type. Must not be given if entryTypes is already specified.
  • entryTypes <string[]> An array of strings identifying the types of <PerformanceEntry> instances the observer is interested in. If not provided an error will be thrown.
  • buffered <boolean> If true, the observer callback is called with a list global PerformanceEntry buffered entries. If false, only PerformanceEntrys created after the time point are sent to the observer callback. Default: false.

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

const {
  performance,
  PerformanceObserver,
} = require('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}`);