🔸argument

a value passed into function as input.

JS ⟩ value ⟩ function ⟩ argument

a value passed into a function, parameter(s) are initialized to these values.

⭐️ 重點

⚖️parameter vs. argument

❗arguments are passed by value❗️

👥 相關

• a function passed into another function as argument is called a callback.

• ...iterable expands an iterable in places where arguments are expected.

💈範例

// ⭐️ parameters:
//   • lie in function's definition (compile-time)
function foo( param1, param2, ... ) { ... }
//           ╰─── parameters ────╯

// ⭐️ arguments:
//   • values passed into function when called (run-time)
//   • parameters are initialized to these values.
//   • can be different on each call.
foo( 1, 'hello', false );
//  ╰─── arguments ───╯

foo( 2, 'world', false );
//  ╰─── arguments ───╯

📗 參考

• JavaScript Tutorial ⟩ Understanding JavaScript Pass-By-Value

📘 手冊

• Argument

• Parameter

• the "arguments" object - an array-like object.

🗣 討論

• Where are arguments positioned in the lexical environment? ⭐️