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JavaScript Academy · Lesson

Profiling intro (Node/DevTools) — tiny timing habits

Profile in tiny steps: measure with console.time/timeEnd and simple timers, find hot code, change one thing, and re-measure.

Why profiling?

Goal: Measure → change → measure again.

  • Use console.time/timeEnd for quick timing
  • Use a tiny now() helper for manual timings
  • Focus on hot code only
  • Make one change at a time
Profiling intro (Node/DevTools) — tiny timing habits — illustration 1

console.time demo

console.time prints how long the labeled block took. Great first step.

// Measure a small loop with console.time/timeEnd
console.time("sum");
let s = 0;
for (let i = 0; i < 100000; i = i + 1) {
  s = s + i;
}
console.timeEnd("sum");
console.log("sum value:", s);
Profiling intro (Node/DevTools) — tiny timing habits — illustration 2

All lessons in this course

  1. Big-O basics, hot vs cold paths (beginner wins)
  2. Avoiding leaks — closures, timers, references
  3. Profiling intro (Node/DevTools) — tiny timing habits
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