perf_hooks.performance

An object that can be used to collect performance metrics from the current Node.js instance. It is similar to window.performance in browsers.

performance.clearMarks(name?): void

If name is not provided, removes all PerformanceMark objects from the Performance Timeline. If name is provided, removes only the named mark.

performance.clearMeasures(name?): void

If name is not provided, removes all PerformanceMeasure objects from the Performance Timeline. If name is provided, removes only the named measure.

performance.clearResourceTimings(name?): void

If name is not provided, removes all PerformanceResourceTiming objects from the Resource Timeline. If name is provided, removes only the named resource.

performance.eventLoopUtilization(utilization1?, utilization2?): Object

This is an alias of perf_hooks.eventLoopUtilization().

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

performance.getEntries(): PerformanceEntry[]

Returns a list of PerformanceEntry objects in chronological order with respect to performanceEntry.startTime. If you are only interested in performance entries of certain types or that have certain names, see performance.getEntriesByType() and performance.getEntriesByName().

performance.getEntriesByName(name, type?): PerformanceEntry[]

Returns a list of PerformanceEntry objects in chronological order with respect to performanceEntry.startTime whose performanceEntry.name is equal to name, and optionally, whose performanceEntry.entryType is equal to type.

performance.getEntriesByType(type): PerformanceEntry[]

Returns a list of PerformanceEntry objects in chronological order with respect to performanceEntry.startTime whose performanceEntry.entryType is equal to type.

performance.mark(name, options?): void

Creates a new PerformanceMark entry in the Performance Timeline. A PerformanceMark is a subclass of PerformanceEntry whose performanceEntry.entryType is always 'mark', and whose performanceEntry.duration is always 0. Performance marks are used to mark specific significant moments in the Performance Timeline.

The created PerformanceMark entry is put in the global Performance Timeline and can be queried with performance.getEntries, performance.getEntriesByName, and performance.getEntriesByType. When the observation is performed, the entries should be cleared from the global Performance Timeline manually with performance.clearMarks.

performance.markResourceTiming(timingInfo, requestedUrl, initiatorType, global, cacheMode, bodyInfo, responseStatus, deliveryType?): void

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

Creates a new PerformanceResourceTiming entry in the Resource Timeline. A PerformanceResourceTiming is a subclass of PerformanceEntry whose performanceEntry.entryType is always 'resource'. Performance resources are used to mark moments in the Resource Timeline.

The created PerformanceMark entry is put in the global Resource Timeline and can be queried with performance.getEntries, performance.getEntriesByName, and performance.getEntriesByType. When the observation is performed, the entries should be cleared from the global Performance Timeline manually with performance.clearResourceTimings.

performance.measure(name, startMarkOrOptions?, endMark?): void

Creates a new PerformanceMeasure entry in the Performance Timeline. A PerformanceMeasure is a subclass of PerformanceEntry whose performanceEntry.entryType is always 'measure', and whose performanceEntry.duration measures the number of milliseconds elapsed since startMark and endMark.

The startMark argument may identify any existing PerformanceMark in the Performance Timeline, or may identify any of the timestamp properties provided by the PerformanceNodeTiming class. If the named startMark does not exist, an error is thrown.

The optional endMark argument must identify any existing PerformanceMark in the Performance Timeline or any of the timestamp properties provided by the PerformanceNodeTiming class. endMark will be performance.now() if no parameter is passed, otherwise if the named endMark does not exist, an error will be thrown.

The created PerformanceMeasure entry is put in the global Performance Timeline and can be queried with performance.getEntries, performance.getEntriesByName, and performance.getEntriesByType. When the observation is performed, the entries should be cleared from the global Performance Timeline manually with performance.clearMeasures.

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

An instance of the PerformanceNodeTiming class that provides performance metrics for specific Node.js operational milestones.

performance.now(): number

Returns the current high resolution millisecond timestamp, where 0 represents the start of the current node process.

performance.setResourceTimingBufferSize(maxSize): void

Sets the global performance resource timing buffer size to the specified number of "resource" type performance entry objects.

By default the max buffer size is set to 250.

The timeOrigin specifies the high resolution millisecond timestamp at which the current node process began, measured in Unix time.

performance.timerify(fn, options?): void

This is an alias of perf_hooks.timerify().

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

performance.toJSON(): void

An object which is JSON representation of the performance object. It is similar to window.performance.toJSON in browsers.

The 'resourcetimingbufferfull' event is fired when the global performance resource timing buffer is full. Adjust resource timing buffer size with performance.setResourceTimingBufferSize() or clear the buffer with performance.clearResourceTimings() in the event listener to allow more entries to be added to the performance timeline buffer.