Behavior of variable and function declarations

Variable and function declarations are moved to the top of their scope before code execution

Occurs during compilation phase

Allows functions to be invoked and variables to be referenced before their explicit declarations

During compilation, functions can be called and variables can be referenced before they are explicitly declared in the code

Only declarations are hoisted, not initializations

Hoisting only applies to the declaration of variables and functions, not their initializations

Variable Hoisting

Variables declared with 'var' are hoisted to the top of their functional or global scope and are automatically initialized with undefined

Function Hoisting

Function declarations are hoisted to the top of their scope, allowing them to be called before they are defined in the code

Class Hoisting

Class declarations are not hoisted and must be declared before they can be used

Variable Scope

Understanding hoisting is crucial for developers to avoid common pitfalls and to write reliable and predictable JavaScript code

Function Declarations vs Expressions

Distinguishing between function declarations and expressions is vital for developers to avoid runtime errors and to structure their code logically

Class Scoping Rules

Developers must be aware of class scoping rules to prevent errors and to create robust object-oriented JavaScript applications

Compilation Phase

During compilation, the engine scans for variable and function declarations, allocating memory for them

Execution Phase

In the execution phase, the code is executed sequentially, initializing and executing variables and functions as they appear