JavaScript Hoisting Explained: How Declarations Move to the Top of Scope

Hoisting is a default JavaScript behavior where variable and function declarations are internally moved to the top of their scope before code executes. Function declarations are fully hoisted, meaning they can be called before they appear in the code. Variables declared with 'var' are hoisted but initialized as 'undefined', so only the declaration moves up, not the assigned value. Variables declared with 'let' and 'const' are also hoisted internally but remain inaccessible before their declaration, throwing a ReferenceError if accessed early. This behavior can be useful for code organization, allowing developers to place high-level logic at the top of a file while keeping implementation details further below.