What is a Closure in JavaScript

• A closure is the combination of a function bundled together (enclosed) with references to its surrounding state (the lexical environment).
• In other words, a closure gives you access to an outer function's scope from an inner function.
• In JavaScript, closures are created every time a function is created, at function creation time.

For example:

In this example the function createFunction is the outer function.
The function displayName is the inner function.

Due to closure the function displayName has access to the name variable. Even after the function createFunction has already run.