JavaScript

IIFE

Definition

Immediately Invoked Function Expression — a function that runs immediately after being defined. IIFEs create a private scope and are used to avoid polluting the global namespace.

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Related Terms

Closure

A function that retains access to variables from its outer (enclosing) scope even after the outer function has returned. Closures are created every time a function is created in JavaScript.

Scope

The region of code where a variable is accessible. JavaScript has global scope, function scope, and block scope. Block scope was introduced with let and const in ES6.

Module

A self-contained unit of code that exports specific values (functions, objects, classes) and imports what it needs from other modules. ES modules use import/export syntax.