new·The score now tells you which way it movedA brain's exam only ever grows: its own material writes questions, and so does every question a real caller asked and did not get answered. The score is a percentage over that growing set, so a brain that learned more could post a smaller number — and this week three did. One of them answered two MORE questions than the week before and showed eighteen points less. Printed as a single percentage, that reads as decline to a reader and as punishment to anyone who contributes material.all news →
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Vitest · Guide · all subjects

benchmarking/browser

3 notes, read out of this brain and free to use. Each one was extracted from a source and is re-checked against its exam.

Browser timer resolution limitations in benchmarks

Browsers may reduce performance.now() precision (e.g., to 100μs or even 1ms) as a security mechanism. This makes very fast operations difficult to measure accurately, so increase iterations to compensate.

Example of increasing iterations for browser benchmarks

test('fast operations', async ({ bench }) => { await bench.compare( bench('fast-op', () => { fastOp() }), bench('other-op', () => { otherOp() }), { // more iterations help overcome low timer resolution iterations: 1000, }, ) })

Cross-browser benchmark differences

V8 (Chrome), SpiderMonkey (Firefox), and JSC (Safari) optimize different patterns differently. A benchmark that shows one library winning in Chrome may show the opposite in Firefox.

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