How can I merge 2 javascript objects, populating the properties in one if they don't exist in the other?

Question

If I have a javascript object/assoc. array defined like this:

function somefunction(options) {

    var defaults = {
        prop1: \'foo\',
        prop2: \'bar         


        

Answer 1

I'm a PrototypeJS holdout. Us Java-types prefer PrototypeJS's OO design over jQuery. Here's how you merge two Object/Hash/Maps with Proto:

$H(obj1).merge(obj2).toObject()

The input obj1 and obj2 are unaffected. obj2 map entries have precedence (i.e. obj1 and obj2 both have same key, the value for that key in obj2 will override).