Trying to join a two-dimensional array in Javascript

Question

I'm trying to convert a two-dimensional array to a string in order to store it in the localStorage array. However, there is something wrong with this code I cannot identify:

for(x in array) {
    if(array[x] instanceof Array) {
        array[x] = array[x].join("`");
    }
}
var string = array.join("@");
localStorage[key] = string;

Does anyone have an idea what I'm doing wrong?

As for what's wrong, by multidimensional array I mean array[0][1] etc. When input into localStorage, all the 'string' is reduced to is @, implying on the other side of the @ there are still arrays.

Answer 1

Nowadays this is as simple as:

[[1,2],[3,4]].map(e => e.join(':')).join(';'); // 1:2;3:4