IK
Interview Knowledge Book
Topics
Practice
Examples
Playground
RU
browser
Closure-backed private counter
Use a closure to keep state private while exposing a small public API.
index.js
function createCounter() { let count = 0; return { increment() { count += 1; return count; }, snapshot() { return count; }, }; } const counterA = createCounter(); const counterB = createCounter(); console.log('counterA', counterA.increment()); console.log('counterA', counterA.increment()); console.log('counterB', counterB.increment()); console.log('counterA snapshot', counterA.snapshot());
Run
Stop
Reset