Performance
Measure, analyze, and optimize application performance.
Eg performance
interface Performance
Deno supports User Timing Level 3 which is not widely supported yet in other runtimes.
Check out the Performance API documentation on MDN for further information about how to use the API.
Methods
mark(
markName: string,
options?: PerformanceMarkOptions,
): PerformanceMark Stores a timestamp with the associated name (a "mark").
measure(
measureName: string,
options?: PerformanceMeasureOptions,
): PerformanceMeasure Stores the DOMHighResTimeStamp duration between two marks along with the associated name (a "measure").
Properties
timeOrigin: number Returns a timestamp representing the start of the performance measurement.
Methods
clearMarks(markName?: string): void Removes the stored timestamp with the associated name.
clearMeasures(measureName?: string): void Removes stored timestamp with the associated name.
clearResourceTimings(): void Removes all performance entries with an entryType of "resource" from the performance timeline and sets the size of the performance resource data buffer to zero.
Note: Deno does not currently track resource timings, so this method has no observable effect. It is provided for API compatibility.
setResourceTimingBufferSize(maxSize: number): void Sets the desired size of the browser's resource timing buffer which stores the "resource" performance entries.
Note: Deno does not currently track resource timings, so this method has no observable effect. It is provided for API compatibility.
getEntriesByName(
name: string,
type?: string,
): PerformanceEntryList getEntriesByType(type: string): PerformanceEntryList mark(
markName: string,
options?: PerformanceMarkOptions,
): PerformanceMark Stores a timestamp with the associated name (a "mark").
measure(
measureName: string,
options?: PerformanceMeasureOptions,
): PerformanceMeasure Stores the DOMHighResTimeStamp duration between two marks along with the associated name (a "measure").
measure(
measureName: string,
startMark?: string,
endMark?: string,
): PerformanceMeasure Stores the DOMHighResTimeStamp duration between two marks along with the associated name (a "measure").
now(): number Returns a current time from Deno's start in fractional milliseconds.
const t = performance.now();
console.log(`${t} ms since start!`);
toJSON(): any Returns a JSON representation of the performance object.
variable Performance
The constructor object for Performance.
The Performance instance is accessed via the global performance property rather than constructed directly, so calling the constructor throws.
Properties
prototype: Performance interface PerformanceEntry
Encapsulates a single performance metric that is part of the performance timeline. A performance entry can be directly created by making a performance mark or measure (for example by calling the .mark() method) at an explicit point in an application.
Properties
Methods
toJSON(): any variable PerformanceEntry
Encapsulates a single performance metric that is part of the performance timeline. A performance entry can be directly created by making a performance mark or measure (for example by calling the .mark() method) at an explicit point in an application.
Properties
prototype: PerformanceEntry interface PerformanceMark
variable PerformanceMark
PerformanceMark is an abstract interface for PerformanceEntry objects with an entryType of "mark". Entries of this type are created by calling performance.mark() to add a named DOMHighResTimeStamp (the mark) to the performance timeline.
Properties
prototype: PerformanceMark interface PerformanceMarkOptions
Options which are used in conjunction with performance.mark. Check out the MDN performance.mark() documentation for more details.
Properties
interface PerformanceMeasure
PerformanceMeasure is an abstract interface for PerformanceEntry objects with an entryType of "measure". Entries of this type are created by calling performance.measure() to add a named DOMHighResTimeStamp (the measure) between two marks to the performance timeline.
Properties
variable PerformanceMeasure
PerformanceMeasure is an abstract interface for PerformanceEntry objects with an entryType of "measure". Entries of this type are created by calling performance.measure() to add a named DOMHighResTimeStamp (the measure) between two marks to the performance timeline.
Properties
prototype: PerformanceMeasure interface PerformanceMeasureOptions
Options which are used in conjunction with performance.measure. Check out the MDN performance.mark() documentation for more details.
Properties
detail: any Metadata to be included in the measure.
start: string | number Timestamp to be used as the start time or string to be used as start mark.
duration: number Duration between the start and end times.
end: string | number Timestamp to be used as the end time or string to be used as end mark.
Properties
detail: any Metadata to be included in the measure.
start: string | number Timestamp to be used as the start time or string to be used as start mark.
duration: number Duration between the start and end times.
end: string | number Timestamp to be used as the end time or string to be used as end mark.
interface PerformanceObserver
Observes performance measurement events and is notified of new PerformanceEntry objects as they are recorded in the performance timeline.
Methods
disconnect(): void Stops the observer from receiving any further performance entries.
observe(options?: { entryTypes?: string[]; type?: string; buffered?: boolean; }): void Specifies the set of performance entry types to observe.
Returns the current list of buffered performance entries, emptying it.
variable PerformanceObserver
Observes performance measurement events and is notified of new PerformanceEntry objects as they are recorded in the performance timeline.
Properties
prototype: PerformanceObserver supportedEntryTypes: readonly string[] interface PerformanceObserverCallback
The callback invoked when the observed set of performance entries grows.
Call Signatures
(
list: PerformanceObserverEntryList,
observer: PerformanceObserver,
): void interface PerformanceObserverEntryList
A list of PerformanceEntry objects passed to a PerformanceObserver callback via its observe() method.
Methods
Returns all explicitly observed performance entries.
getEntriesByName(
name: string,
type?: string,
): PerformanceEntry[] Returns the observed performance entries with the given name.
getEntriesByType(type: string): PerformanceEntry[] Returns the observed performance entries with the given entry type.
variable PerformanceObserverEntryList
A list of PerformanceEntry objects passed to a PerformanceObserver callback via its observe() method.
Properties
prototype: PerformanceObserverEntryList type alias PerformanceEntryList
Definition
variable performance
The global Performance instance, providing access to high-resolution timing via performance.now() and the user-timing marks and measures APIs.
Type
© 2018–2025 the Deno authors
Licensed under the MIT License.
https://docs.deno.com/api/web/performance
