Functions

Function Keyword (regular functions)

Function Declarations

Function declarations define named functions that can be called later in your code, even before the function declaration itself. They start with the function keyword followed by the function name, a list of parameters in parentheses, and the function body enclosed in curly braces.

Function declarations are hoisted, meaning they can be declared below the code that uses them.

Function Expressions

Function expressions define functions as part of an expression, allowing them to be assigned to variables. They can be anonymous (without a name) or named. After declaration they can be invoked by variable name.

Arrow Functions

Arrow functions use another syntax with the arrow => symbol. They are always anonymous, meaning they can only be assigned to a variable or used to declare callbacks in-place. Unlike regular functions, arrow functions don't have their own this keyword. Instead, they inherit it from the outer lexical environment. This is why they can't be used as constructors. Additionally, arrow functions don't have their own arguments array-like object.