Question

Is there a way to apply a two-dimensional array to an object?

Like this:

var myArray = [[0,1],[2,3]];
someObject.apply(null,myArray);

It seems to apply only the first inner array :-/

Why is that?

Answer 1

Okay, since your question was so uninformative I’m going to assume a lot of stuff. Firstly, I’m going to assume that someObject is a function. Next I’m going to assume that it has only one formal parameter like @Adam pointed out. So this is what I assume your code looks like:

function someObject(a) {
    alert(a);                   // were you expecting [[0,1],[2,3]]?
}

var myArray = [[0,1],[2,3]];
someObject.apply(null,myArray);

This is what I think you want instead:

function someObject() {
    alert(arguments);           // now it alerts [[0,1],[2,3]]
}

var myArray = [[0,1],[2,3]];
someObject.apply(null,myArray);

Remember, when you apply arguments to a function you pass it the arguments as an array. It’s kind of like calling the function as follows:

function someObject() {
    alert(arguments);
}

var myArray = [[0,1],[2,3]];
someObject(myArray[0], myArray[1]);

Of course, it also assigns the function a custom this pointer.

Edit: Looking back at your code I think you might have intended to use call instead of apply. The method call allows you to pass the arguments to the function as separate arguments instead of an array of arguments. So your code would look:

function someObject(a, b) {
    alert(a);                  // now a is [[0,1],[2,3]]
    alert(b);                  // b is 5 and so on
}

var myArray = [[0,1],[2,3]];
someObject.call(null,myArray,5);