Merging objects (associative arrays)

Question

What’s the best/standard way of merging two associative arrays in JavaScript? Does everyone just do it by rolling their own for loop?

Answer 1

I needed a deep-object-merging. So all of the other answers didn't help me very much. _.extend and jQuery.extend do well, unless you have a recursive array like i do. But it ain't so bad, you can program it in five minutes:

var deep_merge = function (arr1, arr2) {
    jQuery.each(arr2, function (index, element) {
        if (typeof arr1[index] === "object" && typeof element === "object") {
            arr1[index] = deep_merge(arr1[index], element);
        } else if (typeof arr1[index] === "array" && typeof element === "array") {
            arr1[index] = arr1[index].concat(element);
        } else {
            arr1[index] = element;
        }
    });
    return arr1;
}