What Happens When Variables and Functions Are Hoisted in JavaScript?

Hoisting is JavaScript’s default behavior where variable and function declarations are moved to the top of their scope during the compilation phase, before code execution.

Only declarations are hoisted, not initializations.

• Function declarations are fully hoisted and can be used before they are defined.
• Variables declared with var are hoisted but initialized as undefined.
• Variables declared with let and const are hoisted but remain in a Temporal Dead Zone until their declaration is reached.

Hoisting happens per scope (global, function, block) and is handled by JavaScript’s execution context creation phase.