Why is my join on a JavaScript array failing?

Question

I have a function that accepts multiple arguments (only one is defined in the function though)

var getSearchFields = function(method) {

    console.log(arguments); // this prints them out nicely into the console

    var args = arguments;

    var argsString = args.join('/'); // I expect 'arg1/arg2/arg3', instead I get 'args.join is not a function'
}

I just want a string of all the arguments being sent to the function. I keep getting this error:

args.join is not a function

Can someone please tell me what I'm doing wrong?

Thanks

Answer 1

arguments is a pseudo-array, not a real one. The join method is available for arrays.

You'll need to cheat:

var convertedArray = [];

for(var i = 0; i < arguments.length; ++i)
{
 convertedArray.push(arguments[i]);
}

var argsString = convertedArray.join('/');

Similar to other posts, you can do the following as shorthand:

var argsString = Array.prototype.join.call(arguments, "/");

Answer 2

arguments is not a JavaScript array; it's a special object that doesn't have a join method.

Answer 3

arguments is not really an array.

try this:

var args = [].splice.call(arguments,0);
var argsString = args.join('/');

Answer 4

As all said above, the arguments object is not really an array, but you can apply array functions directly, by accessing the Array.prototype and executing them with apply or call to change the context:

var argsString = Array.prototype.join.call(arguments, '/');