Interface Performance

    Provides access to performance-related information for the current page. It's part of the High Resolution Time API, but is enhanced by the Performance Timeline API, the Navigation Timing API, the User Timing API, and the Resource Timing API.

    MDN Reference

    interface Performance {
        eventCounts: EventCounts;
        navigation: PerformanceNavigation;
        onresourcetimingbufferfull: (this: Performance, ev: Event) => any;
        timeOrigin: number;
        timing: PerformanceTiming;
        addEventListener<K extends "resourcetimingbufferfull">(
            type: K,
            listener: (this: Performance, ev: PerformanceEventMap[K]) => any,
            options?: boolean | AddEventListenerOptions,
        ): void;
        addEventListener(
            type: string,
            listener: EventListenerOrEventListenerObject,
            options?: boolean | AddEventListenerOptions,
        ): void;
        clearMarks(markName?: string): void;
        clearMeasures(measureName?: string): void;
        clearResourceTimings(): void;
        dispatchEvent(event: Event): boolean;
        getEntries(): PerformanceEntryList;
        getEntriesByName(name: string, type?: string): PerformanceEntryList;
        getEntriesByType(type: string): PerformanceEntryList;
        mark(
            markName: string,
            markOptions?: PerformanceMarkOptions,
        ): PerformanceMark;
        measure(
            measureName: string,
            startOrMeasureOptions?: string | PerformanceMeasureOptions,
            endMark?: string,
        ): PerformanceMeasure;
        now(): number;
        removeEventListener<K extends "resourcetimingbufferfull">(
            type: K,
            listener: (this: Performance, ev: PerformanceEventMap[K]) => any,
            options?: boolean | EventListenerOptions,
        ): void;
        removeEventListener(
            type: string,
            listener: EventListenerOrEventListenerObject,
            options?: boolean | EventListenerOptions,
        ): void;
        setResourceTimingBufferSize(maxSize: number): void;
        toJSON(): any;
    }
    Hierarchy

    Properties

    eventCounts navigation onresourcetimingbufferfull timeOrigin timing

    Methods

    addEventListener clearMarks clearMeasures clearResourceTimings dispatchEvent getEntries getEntriesByName getEntriesByType mark measure now removeEventListener setResourceTimingBufferSize toJSON

    Properties

    ReadonlyeventCounts

    eventCounts: EventCounts

    MDN Reference

    Readonlynavigation

    navigation: PerformanceNavigation

    Deprecated

    MDN Reference

    onresourcetimingbufferfull

    onresourcetimingbufferfull: (this: Performance, ev: Event) => any

    MDN Reference

    ReadonlytimeOrigin

    timeOrigin: number

    MDN Reference

    Readonlytiming

    timing: PerformanceTiming

    Deprecated

    MDN Reference

    Methods

    addEventListener

    • addEventListener<K extends "resourcetimingbufferfull">(
          type: K,
          listener: (this: Performance, ev: PerformanceEventMap[K]) => any,
          options?: boolean | AddEventListenerOptions,
      ): void

    • Appends an event listener for events whose type attribute value is type. The callback argument sets the callback that will be invoked when the event is dispatched.

      The options argument sets listener-specific options. For compatibility this can be a boolean, in which case the method behaves exactly as if the value was specified as options's capture.

      When set to true, options's capture prevents callback from being invoked when the event's eventPhase attribute value is BUBBLING_PHASE. When false (or not present), callback will not be invoked when event's eventPhase attribute value is CAPTURING_PHASE. Either way, callback will be invoked if event's eventPhase attribute value is AT_TARGET.

      When set to true, options's passive indicates that the callback will not cancel the event by invoking preventDefault(). This is used to enable performance optimizations described in § 2.8 Observing event listeners.

      When set to true, options's once indicates that the callback will only be invoked once after which the event listener will be removed.

      If an AbortSignal is passed for options's signal, then the event listener will be removed when signal is aborted.

      The event listener is appended to target's event listener list and is not appended if it has the same type, callback, and capture.

      MDN Reference

      Type Parameters

      • K extends "resourcetimingbufferfull"

      Parameters

      Returns void

    • addEventListener(
          type: string,
          listener: EventListenerOrEventListenerObject,
          options?: boolean | AddEventListenerOptions,
      ): void

    • Appends an event listener for events whose type attribute value is type. The callback argument sets the callback that will be invoked when the event is dispatched.

      The options argument sets listener-specific options. For compatibility this can be a boolean, in which case the method behaves exactly as if the value was specified as options's capture.

      When set to true, options's capture prevents callback from being invoked when the event's eventPhase attribute value is BUBBLING_PHASE. When false (or not present), callback will not be invoked when event's eventPhase attribute value is CAPTURING_PHASE. Either way, callback will be invoked if event's eventPhase attribute value is AT_TARGET.

      When set to true, options's passive indicates that the callback will not cancel the event by invoking preventDefault(). This is used to enable performance optimizations described in § 2.8 Observing event listeners.

      When set to true, options's once indicates that the callback will only be invoked once after which the event listener will be removed.

      If an AbortSignal is passed for options's signal, then the event listener will be removed when signal is aborted.

      The event listener is appended to target's event listener list and is not appended if it has the same type, callback, and capture.

      MDN Reference

      Parameters

      Returns void

    clearMarks

    • clearMarks(markName?: string): void

    • MDN Reference

      Parameters

      • OptionalmarkName: string

      Returns void

    clearMeasures

    • clearMeasures(measureName?: string): void

    • MDN Reference

      Parameters

      • OptionalmeasureName: string

      Returns void

    clearResourceTimings

    dispatchEvent

    • dispatchEvent(event: Event): boolean

    • Dispatches a synthetic event event to target and returns true if either event's cancelable attribute value is false or its preventDefault() method was not invoked, and false otherwise.

      MDN Reference

      Parameters

      Returns boolean

    getEntries

    getEntriesByName

    getEntriesByType

    mark

    measure

    now

    removeEventListener

    setResourceTimingBufferSize

    • setResourceTimingBufferSize(maxSize: number): void

    • MDN Reference

      Parameters

      • maxSize: number

      Returns void

    toJSON

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