declare module 'perf_hooks' { import { AsyncResource } from 'async_hooks'; type EntryType = 'node' | 'mark' | 'measure' | 'gc' | 'function' | 'http2' | 'http'; interface PerformanceEntry { /** * The total number of milliseconds elapsed for this entry. * This value will not be meaningful for all Performance Entry types. */ readonly duration: number; /** * The name of the performance entry. */ readonly name: string; /** * The high resolution millisecond timestamp marking the starting time of the Performance Entry. */ readonly startTime: number; /** * The type of the performance entry. * Currently it may be one of: 'node', 'mark', 'measure', 'gc', or 'function'. */ readonly entryType: EntryType; /** * When `performanceEntry.entryType` is equal to 'gc', `the performance.kind` property identifies * the type of garbage collection operation that occurred. * See perf_hooks.constants for valid values. */ readonly kind?: number | undefined; /** * When `performanceEntry.entryType` is equal to 'gc', the `performance.flags` * property contains additional information about garbage collection operation. * See perf_hooks.constants for valid values. */ readonly flags?: number | undefined; } interface PerformanceNodeTiming extends PerformanceEntry { /** * The high resolution millisecond timestamp at which the Node.js process completed bootstrap. */ readonly bootstrapComplete: 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. */ readonly environment: number; /** * The high resolution millisecond timestamp at which the Node.js environment was initialized. */ readonly idleTime: 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. */ readonly loopExit: 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. */ readonly loopStart: number; /** * The high resolution millisecond timestamp at which the V8 platform was initialized. */ readonly v8Start: number; } interface EventLoopUtilization { idle: number; active: number; utilization: number; } interface Performance { /** * If name is not provided, removes all PerformanceMark objects from the Performance Timeline. * If name is provided, removes only the named mark. * @param name */ clearMarks(name?: string): 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. * @param name */ mark(name?: string): 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 the Performance Timeline, or may identify * any of the timestamp properties provided by the PerformanceNodeTiming class. If the named startMark does not exist, * then startMark is set to timeOrigin by default. * * The endMark argument must identify any existing PerformanceMark in the the Performance Timeline or any of the timestamp * properties provided by the PerformanceNodeTiming class. If the named endMark does not exist, an error will be thrown. * @param name * @param startMark * @param endMark */ measure(name: string, startMark?: string, endMark?: string): void; /** * An instance of the PerformanceNodeTiming class that provides performance metrics for specific Node.js operational milestones. */ readonly nodeTiming: PerformanceNodeTiming; /** * @return the current high resolution millisecond timestamp */ now(): number; /** * The timeOrigin specifies the high resolution millisecond timestamp from which all performance metric durations are measured. */ readonly timeOrigin: number; /** * Wraps a function within a new function that measures the running time of the wrapped function. * A PerformanceObserver must be subscribed to the 'function' event type in order for the timing details to be accessed. * @param fn */ timerify any>(fn: T): T; /** * eventLoopUtilization is similar to CPU utilization except that it is calculated using high precision wall-clock time. * It represents the percentage of time the event loop has spent outside the event loop's event provider (e.g. epoll_wait). * No other CPU idle time is taken into consideration. * * @param util1 The result of a previous call to eventLoopUtilization() * @param util2 The result of a previous call to eventLoopUtilization() prior to util1 */ eventLoopUtilization(util1?: EventLoopUtilization, util2?: EventLoopUtilization): EventLoopUtilization; } interface PerformanceObserverEntryList { /** * @return a list of PerformanceEntry objects in chronological order with respect to performanceEntry.startTime. */ getEntries(): PerformanceEntry[]; /** * @return 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. */ getEntriesByName(name: string, type?: EntryType): PerformanceEntry[]; /** * @return Returns a list of PerformanceEntry objects in chronological order with respect to performanceEntry.startTime * whose performanceEntry.entryType is equal to type. */ getEntriesByType(type: EntryType): PerformanceEntry[]; } type PerformanceObserverCallback = (list: PerformanceObserverEntryList, observer: PerformanceObserver) => void; class PerformanceObserver extends AsyncResource { constructor(callback: PerformanceObserverCallback); /** * Disconnects the PerformanceObserver instance from all notifications. */ disconnect(): void; /** * Subscribes the PerformanceObserver instance to notifications of new PerformanceEntry instances identified by options.entryTypes. * When options.buffered is false, the callback will be invoked once for every PerformanceEntry instance. * Property buffered defaults to false. * @param options */ observe(options: { entryTypes: ReadonlyArray; buffered?: boolean | undefined }): void; } namespace constants { const NODE_PERFORMANCE_GC_MAJOR: number; const NODE_PERFORMANCE_GC_MINOR: number; const NODE_PERFORMANCE_GC_INCREMENTAL: number; const NODE_PERFORMANCE_GC_WEAKCB: number; const NODE_PERFORMANCE_GC_FLAGS_NO: number; const NODE_PERFORMANCE_GC_FLAGS_CONSTRUCT_RETAINED: number; const NODE_PERFORMANCE_GC_FLAGS_FORCED: number; const NODE_PERFORMANCE_GC_FLAGS_SYNCHRONOUS_PHANTOM_PROCESSING: number; const NODE_PERFORMANCE_GC_FLAGS_ALL_AVAILABLE_GARBAGE: number; const NODE_PERFORMANCE_GC_FLAGS_ALL_EXTERNAL_MEMORY: number; const NODE_PERFORMANCE_GC_FLAGS_SCHEDULE_IDLE: number; } const performance: Performance; interface EventLoopMonitorOptions { /** * The sampling rate in milliseconds. * Must be greater than zero. * @default 10 */ resolution?: number | undefined; } interface EventLoopDelayMonitor { /** * Enables the event loop delay sample timer. Returns `true` if the timer was started, `false` if it was already started. */ enable(): boolean; /** * Disables the event loop delay sample timer. Returns `true` if the timer was stopped, `false` if it was already stopped. */ disable(): boolean; /** * Resets the collected histogram data. */ reset(): void; /** * Returns the value at the given percentile. * @param percentile A percentile value between 1 and 100. */ percentile(percentile: number): number; /** * A `Map` object detailing the accumulated percentile distribution. */ readonly percentiles: Map; /** * The number of times the event loop delay exceeded the maximum 1 hour eventloop delay threshold. */ readonly exceeds: number; /** * The minimum recorded event loop delay. */ readonly min: number; /** * The maximum recorded event loop delay. */ readonly max: number; /** * The mean of the recorded event loop delays. */ readonly mean: number; /** * The standard deviation of the recorded event loop delays. */ readonly stddev: number; } function monitorEventLoopDelay(options?: EventLoopMonitorOptions): EventLoopDelayMonitor; } declare module 'node:perf_hooks' { export * from 'perf_hooks'; }