Modify object using jQuery.map?

Question

I have a key-value pair like

var classes = { red: 'Red', green: 'Green' };

How can I prepend each of the keys with a specific value? Could this be done using jQuery.map?

The final result I'm looking for is

classes = { 'a-red': 'Red', 'a-green': 'Green' };

Answer 1

Something like this would work:

function prependObj(obj, prefix) {
  var result = {};
  for(var i in obj) if(obj.hasOwnProperty(i)) result[prefix+i] = obj[i];
  return result;
}

Then you'd call it like this:

classes = prependObj(classes, "a-");

You can test it here. This does not modify the original object and doesn't have any jQuery dependency, so you can use it with or without.