when to use arguments in a function javaScript code example

Example 1: javascript function variable arguments

function foo() {
  for (var i = 0; i < arguments.length; i++) {
    console.log(arguments[i]);
  }
}

foo(1,2,3);
//1
//2
//3

Example 2: js unspecified parameters

function my_log(...args) {
     // args is an Array
     console.log(args);
     // You can pass this array as parameters to another function
     console.log(...args);
}