JavaScript Parameters vs Arguments: Default and Rest Parameters Explained

JavaScript functions rely on four closely related concepts: parameters, arguments, default parameters, and rest parameters. Parameters are the named variables defined in a function declaration, while arguments are the actual values supplied when the function is called. Default parameters allow a fallback value to be used when no argument is provided, preventing undefined outputs. Rest parameters, using the spread syntax, enable a function to accept an indefinite number of arguments by collecting them into an array. Together, these four concepts form the foundation of how JavaScript functions receive and handle data.