Performance

performance, PerformanceObserver, and the PerformanceEntry classes are globals and follow the User Timing and Performance Timeline specs.

Example

// performance.mjs
const start = performance.now();
performance.mark("parse:start");
JSON.parse(JSON.stringify(Array.from({ length: 1000 }, (_, i) => ({ i }))));
performance.mark("parse:end", { detail: { rows: 1000 } });

const measure = performance.measure("parse", "parse:start", "parse:end");
console.log(measure.entryType, measure.name, measure.duration >= 0);
console.log(performance.getEntriesByName("parse:end")[0].detail.rows);
console.log(performance.now() >= start, typeof performance.timeOrigin);

utf-8 · js · Lines: 10

elide run performance.mjs prints:

text

measure parse true
1000
true number

utf-8 · text · Lines: 3

Differences from browsers

performance and node:perf_hooks share one timeline.
PerformanceObserver.supportedEntryTypes is mark, measure, node, and function.
Mark and measure detail values are cloned as in Web Messaging; functions throw DataCloneError.

Reference

Status: Full · Not measured · since 1.1.0

Exports

Export	Kind	Status	Notes
`PerformanceEntry`	class	Full	`name`, `entryType`, `startTime`, `duration`, `detail`, `toJSON()`
`PerformanceMark`	class	Full	`detail`
`PerformanceMeasure`	class	Full	`detail`
`PerformanceObserverEntryList`	class	Full	`getEntries()`, `getEntriesByName()`, `getEntriesByType()`
`PerformanceObserver`	class	Full	`observe()`, `disconnect()`, `takeRecords()`, `PerformanceObserver.supportedEntryTypes`
`Performance`	class	Full	`now()`, `timeOrigin`, `mark()`, `measure()`, `getEntries()`, `getEntriesByName()`, `getEntriesByType()`, `clearMarks()`, `clearMeasures()`, `toJSON()`