25 lines
847 B
JavaScript
25 lines
847 B
JavaScript
function testTimeResolution(highResTimeFunc, funcString) {
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test(() => {
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const t0 = highResTimeFunc();
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let t1 = highResTimeFunc();
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while (t0 == t1) {
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t1 = highResTimeFunc();
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}
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const epsilon = 1e-5;
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assert_greater_than_equal(t1 - t0, 0.005 - epsilon, 'The second ' + funcString + ' should be much greater than the first');
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}, 'Verifies the resolution of ' + funcString + ' is at least 5 microseconds.');
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}
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function timeByPerformanceNow() {
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return performance.now();
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}
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function timeByUserTiming() {
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performance.mark('timer');
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const time = performance.getEntriesByName('timer')[0].startTime;
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performance.clearMarks('timer');
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return time;
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}
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testTimeResolution(timeByPerformanceNow, 'performance.now()');
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testTimeResolution(timeByUserTiming, 'entry.startTime');
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