Recursive Object Extend

obj-extend-recursive.js

var extend = function(output) {
  output = output || {};
  
  // no args so just return output
  if ( arguments.length < 2) return output;

  // loop over arguments and recurse if prop is an object
  for (var i = 1, len = arguments.length; i < len; i++) {
    var obj = arguments[i];

    if (!obj)
      continue;

    for (var key in obj) {
      if (obj.hasOwnProperty(key)) {
        if (typeof obj[key] === 'object')
          extend(output[key], obj[key]);
        else
          output[key] = obj[key];
      }
    }
  }

  return output;
};

extend({}, objA, objB);