converting between types in javascript

Question

I need to write a function that returns the last element from the input arguments. This is easy for Strings and Arrays, but the function can also accept a "list of arguments". I have tried to process this list of arguments with String and Array syntax, but I get errors about object not having method x. This is what I have so far:

function last(list){
 // return last element of array
 if(list instanceof Array){
 return list[list.length-1];
 }
 // return last element of string
 else if(typeof list === 'string'){
 return list.substring(list.length-1, list.length);
 }
}

Is there a way to convert an arbitrary list of arguments to a String or Array? Here is an example of what I mean by list of arguments.

Test.assertEquals(last(1,"b",3,"d",5), 5);

• CrayonViolent: can you give an example of what is giving you the error

Answer 1

Look at the "arguments" object. So something like

function last(list) {
 if (arguments.length > 1) {
 return arguments[arguments.length-1];
 }
 else {
 ... (as now)
 }

• user137717: if the argument is a single array, will arguments[arguments.length-1] return the last value of the array or a reference to the array?
• mayorbyrne: if the argument itself is [1, 2, 3], arguments[arguments.length-1] will return [1, 2, 3], not the values inside

Answer 2

You can just call arguments[arguments.length -1] inside the function, and it should give you the last argument, regardless of type.

Here's the resource on arguments: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/arguments