Passing unlimited params to a javascript function

I need to know how to pass unknown/unlimited parameters to a javascript function. What I want to do is make a simple function that will concatenate any strings passed to a comma delimted string, and then return that string. For example:
var commaDelimitedString = getConcat('dog','cat',bird');
Ok, silly example, but I might pass three string, I might pass 100, who knows? So how do I write the function to accept any number of params and then act on them?
I know I saw something once like this:
function someFunction(...) {
..
}
And then the params are acted on as an array, but for the life of me ,I can't figure out the correct Google search terms to find it. Any help would be greatly appreciated.