Variable Scope

Terminology

Scope

Where a variable is available in your code.

Global

All code that is not inside a function.

Global Scope

Variables that are available anywhere in your code (even inside functions).

Code Block

Javascript that is surrounded by curly braces {} such as inside if / else if / else, loops and functions.

Block Scope

let and const variables that are declared inside a code block are only available within that block. In other words, they are local variables.

Function Scope

All variables defined inside a function are only available inside that function.

Execution Context

A wrapper to help manage the code that is running. The scope that is currently running is managed via execution contexts.