Course Content
Introduction to JavaScript
Introduction to JavaScript
Arguments
Arguments are function variables that you can use only inside the function:
function funcName(a, b) { console.log("Arg A =", a); console.log("Arg B =", b); }; funcName(15, 24); console.log(a); // This will raise an Error
Also, if you name the arguments the same as the variables outside the function, the function will use the arguments instead of the variables:
let a = 15; function num(a) { console.log("(func) a =", a); }; num(20); console.log("(global) a =", a);
Note
When the function finishes execution, its space disappears, and all arguments lose their values.
Arguments are received sequentially:
function numSet(a, b, c) { console.log([a ** 2, b + 2, c - 10]); }; numSet(15, 12, 99);
Unfilled arguments will receive the value undefined
and will not be displayed in any way. Redundant arguments will not be used:
function numSet(a, b, c) { console.log([a, b, c]); } numSet(12, 13); numSet(15, 12, 13, 15);
The function receives values as arguments. Variables outside the function remain unchanged. An argument is an independent value inside a function:
let a = 15; function add(numb) { numb += 5; console.log("(func) numb =", numb); }; add(a); console.log("(global) a =", a);
Note
This does not work the same way for arrays because an array contains a reference to some data. This reference is passed to the function, so changes inside the function affect the data outside. This will be studied in the "OOP in JavaScript" course.
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