function recognised as variable parameters code example

Example 1: javascript check if argument is passed

function func(arg1, arg2) {
  if (typeof arg2 === "undefined") {
    arg2 = "defaultValue";
  }
  
  //Rest of function
}

Example 2: 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