JavaScript variable number of arguments to function

In (most) recent browsers, you can accept variable number of arguments with this syntax:

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

Here's a small example:

function foo(x, ...args) {
  console.log(x, args, ...args, arguments);
}

foo('a', 'b', 'c', z='d')

=>

a
Array(3) [ "b", "c", "d" ]
b c d
Arguments
​    0: "a"
    ​1: "b"
    ​2: "c"
    ​3: "d"
    ​length: 4

Documentation and more examples here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters

Sure, just use the arguments object.

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