performance

namespace

js/performance.js:101

WebAPI-style benchmarking API
For more information, see: https://developer.mozilla.org/en-US/docs/Web/API/Performance_API

propertyreadonly

timeOrigin

js/performance.js:211

timeOrigin: number = 0.0 };

Read-only property of the Performance interface returns the high resolution timestamp that is used as the baseline for performance-related timestamps.
In JSplitter context this value represents the "UNIX-time" (milliseconds since 1 January 1970) when script was loaded.

Default

0.0 };

method

clearMarks

js/performance.js:183

clearMarks(name)

Removes all or specific PerformanceEntry objects from the player's performance timeline.

Parameters

Name	Type	Description
`name = ''`optional	`string`	A string representing the name of the PerformanceEntry object. If this argument is omitted, all entries with an entryType of "mark" will be removed.

method

clearMeasures

js/performance.js:189

clearMeasures(name)

Removes all or specific PerformanceEntry objects from the player's performance timeline.

Parameters

Name	Type	Description
`name = ''`optional	`string`	A string representing the name of the PerformanceEntry object. If this argument is omitted, all entries with an entryType of "measure" will be removed.

method

getEntries

js/performance.js:159

getEntries()

Returns an array of all PerformanceEntry objects currently present in the performance timeline.
If you are only interested in performance entries of certain types ("mark" or "measure") or that have certain names, see getEntriesByType and getEntriesByName.

Returns

Array<PerformanceEntry>

method

getEntriesByName

js/performance.js:174

getEntriesByName(name, type)

Returns an array of PerformanceEntry objects currently present in the performance timeline with the given name and type ("mark" or "measure").
If you are interested in performance entries of certain types, see getEntriesByType. For all performance entries, see getEntries.

Parameters

Name	Type	Description
`name`	`string`	A string representing the name of the measure.
`type = ''`optional	`string`	A string representing the name of the measure.

Returns

Array<PerformanceEntry>

method

getEntriesByType

js/performance.js:166

getEntriesByType(type)

Returns an array of PerformanceEntry objects currently present in the performance timeline for a given type ("mark" or "measure").
If you are interested in performance entries of certain name, see getEntriesByName. For all performance entries, see getEntries.

Parameters

Name	Type	Description
`type`	`string`	A string representing the name of the measure.

Returns

Array<PerformanceEntry>

method

mark

js/performance.js:122

mark(name, markOptions)

Creates a named PerformanceEntry object representing a high resolution timestamp marker in the player's performance timeline

Parameters

Name	Type	Description
`name`	`string`	A string representing the name of the mark.
`markOptions = null`optional	`object`	An object for specifying a timestamp and additional metadata for the mark. Consists of two optional properties: detail: Arbitrary metadata to include in the mark. Defaults to null. Can be an object of any type startTime: Value to use as the mark time. Defaults to performance.now()

Example

performance.mark('work-begin', { detail: { description: "Begin of some important work", id: 777 } });
doSomething();
performance.mark('work-end');
const measure = performance.measure('work-duration', 'work-begin', 'work-end');
const beginMark = performance.getEntriesByName('work-begin')[0];
console.log(`"${beginMark.detail.description}" started for id = ${beginMark.detail.id} executed in ${measure.duration} ms`);
performance.clearMarks();
performance.clearMeasures();

method

measure

js/performance.js:142

measure(measureName, startMark, endMark, measureOptions)

Creates a named PerformanceEntry object representing a time measurement between two marks in the player's performance timeline.
When measuring between two marks, there is a start mark and end mark, respectively. The named timestamp is referred to as a measure.
If only measureName is specified, the start timestamp is set to zero, and the end timestamp (which is used to calculate the duration) is the value that would be returned by performance.now()

Parameters

Name	Type	Description
`measureName`	`string`	A string representing the name of the measure.
`startMark = ''`optional	`string`	A string naming a PerformanceEntry with "mark" type in the performance timeline. The PerformanceEntry.startTime property of this mark will be used for calculating the measure.
`endMark = ''`optional	`string`	A string naming a PerformanceEntry with "mark" type in the performance timeline. The PerformanceEntry.startTime property of this mark will be used for calculating the measure.
`measureOptions = null`optional	`object`	An object for specifying a timestamp and additional metadata for the mark. Consists of two optional properties: detail: Arbitrary metadata to include in the mark. Defaults to null. Can be an object of any type start: Value to use as the mark time. Defaults to performance.now() duration: Value to use as the mark time. Defaults to performance.now() end: Value to use as the mark time. Defaults to performance.now()

Returns

PerformanceEntry

method

now

js/performance.js:108

now()

Returns a high resolution timestamp in milliseconds with a fractional part. It represents the time elapsed since performance.timeOrigin (the time when script was loaded)
Unlike Date.now, the timestamps returned by performance.now() are not limited to one-millisecond resolution. Instead, they represent times as floating-point numbers with up to microsecond precision.
Also, Date.now() may have been impacted by system and user clock adjustments, clock skew, etc. as it is relative to the Unix epoch (1970-01-01T00:00:00Z) and dependent on the system clock.
The performance.now() method on the other hand is relative to the timeOrigin property which is a monotonic clock: its current time never decreases and isn't subject to adjustments.

Returns

number

Example

const t0 = performance.now();
doSomething();
const t1 = performance.now();
console.log(`Call to doSomething took ${t1 - t0} milliseconds.`);

method

Observer

js/performance.js:202

Observer(callback)

Creates and returns a new PerformanceObserver object.

The observer callback is invoked when performance entry events are recorded by performance.mark() or performance.measure() calls for the entry types that have been registered, via the observe() method.

Parameters

Name	Type	Description
`callback`	`function`

Returns

PerformanceObserver

method

toString

js/performance.js:195

toString(measureName, startMark, endMark, measureOptions)

Returns string representation of Performance object.
This gives you a list of all performance entries in a human-readable form.

Returns

string