Scope & Closures in JavaScript
From the JavaScript cheat sheet · Functions · verified Jul 2026
Scope & Closures
Understanding scope and closure behavior
javascript
// Global scope
let global = 'everywhere';
// Function scope
function outer() {
let outerVar = 'outer';
function inner() {
let innerVar = 'inner';
console.log(outerVar); // accessible
}
}
// Closure
function counter() {
let count = 0;
return () => ++count;
}💡 Functions create new scope, blocks create scope for let/const
⚡ Closures remember variables from outer scope even after function returns
📌 var is function-scoped, let/const are block-scoped
🔥 Closures are commonly used for data privacy and factory functions
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