What is an arguments object

The arguments object is an Array-like object accessible inside functions that contains the values of the arguments passed to that function. For example, let's see how to use arguments object inside sum function,

  function sum() {
    var total = 0;
    for (var i = 0, len = arguments.length; i < len; ++i) {
      total += arguments[i];
    }
    return total;
  }

  sum(1, 2, 3); // returns 6

Note: You can't apply array methods on arguments object. But you can convert into a regular array as below.

  var argsArray = Array.prototype.slice.call(arguments);