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PerformanceNodeTiming

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class PerformanceNodeTiming extends PerformanceEntry

This property is an extension by Node.js. It is not available in Web browsers.

Provides timing details for Node.js itself. The constructor of this class is not exposed to users.

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performanceNodeTiming.bootstrapComplete

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Type:number

The high resolution millisecond timestamp at which the Node.js process completed bootstrapping. If bootstrapping has not yet finished, the property has the value of -1.

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performanceNodeTiming.environment

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Type:number

The high resolution millisecond timestamp at which the Node.js environment was initialized.

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performanceNodeTiming.idleTime

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Type:number

The high resolution millisecond timestamp of the amount of time the event loop has been idle within the event loop's event provider (e.g. epoll_wait). This does not take CPU usage into consideration. If the event loop has not yet started (e.g., in the first tick of the main script), the property has the value of 0.

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performanceNodeTiming.loopExit

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Type:number

The high resolution millisecond timestamp at which the Node.js event loop exited. If the event loop has not yet exited, the property has the value of -1. It can only have a value of not -1 in a handler of the 'exit' event.

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performanceNodeTiming.loopStart

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Type:number

The high resolution millisecond timestamp at which the Node.js event loop started. If the event loop has not yet started (e.g., in the first tick of the main script), the property has the value of -1.

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performanceNodeTiming.nodeStart

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Type:number

The high resolution millisecond timestamp at which the Node.js process was initialized.

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performanceNodeTiming.uvMetricsInfo

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Returns:Object
loopCount:number
Number of event loop iterations.
events:number
Number of events that have been processed by the event handler.
eventsWaiting:number
Number of events that were waiting to be processed when the event provider was called.

This is a wrapper to the uv_metrics_info function. It returns the current set of event loop metrics.

It is recommended to use this property inside a function whose execution was scheduled using setImmediate to avoid collecting metrics before finishing all operations scheduled during the current loop iteration.

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

setImmediate(() => {
  console.log(performance.nodeTiming.uvMetricsInfo);
});
import { performance } from 'node:perf_hooks';

setImmediate(() => {
  console.log(performance.nodeTiming.uvMetricsInfo);
});
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performanceNodeTiming.v8Start

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Type:number

The high resolution millisecond timestamp at which the V8 platform was initialized.