Create and run micro-benchmarks in the browser to compare the execution speed of different JavaScript implementations. Add multiple test cases, run them thousands of times, and see operations per second results.
Ops/sec (operations per second) measures how many times a code block can execute in one second. Higher is faster.
The benchmark runs in your browser JavaScript engine. Results vary by device. Use it for relative comparisons.
Key factors: JIT may optimize away test code, GC pauses, background browser tasks, CPU throttling, and cache warm-up effects. For reliable results: run multiple times, close other tabs, ensure test code has observable side effects to prevent engine optimization.
Common pitfalls include: not warming up the JIT compiler, too few iterations, environment mismatch with production, and GC interference. Best practices: run multiple iterations and average results, test hot and cold paths separately, run in an isolated environment, and use dedicated tools (wrk, JMH, Benchmark.js) rather than simple timers.