JavaScript equivalent of jQuery's extend method

Question

Background

I have a function that takes a config object as an argument. Within the function, I also have default object. Each of those

Answer 1

I prefer this code that uses my generic forEachIn, and does not mangle the first object:

function forEachIn(obj, fn) {
    var index = 0;
    for (var key in obj) {
        if (obj.hasOwnProperty(key)) {
            fn(obj[key], key, index++);
        }
    }
}

function extend() {
    var result = {};
    for (var i = 0; i < arguments.length; i++) {
        forEachIn(arguments[i],
            function(obj, key) {
                result[key] = obj;
            });
    }
    return result;
}

If you really do want to merge stuff into the first object, you can do:

obj1 = extend(obj1, obj2);