angular.extend - shallow + deep copy (supports merging of arrays and deduping)

angular-deep-extend.js

/**
 * Deep copy example:
 * angular.extend(true, { hello: 'world', app: { id: '1234', groups: [{ id: 1},2,3,4,5] }, ids: [1,2,3] }, { app: { name: 'bond', groups: [6, 7, {hello:'world', test: [1,2,3,4, [12,34,45]]}, 9] }, ids: [4,5,6,3] });
 * => "{"hello":"world","app":{"id":"1234","groups":[{"id":1},2,3,4,5,6,7,{"hello":"world","test":[1,2,3,4,[12,34,45]]},9],"name":"bond"},"ids":[1,2,3,4,5,6,3]}"
 *
 * Deep copy and dedup arrays
 * angular.extend(true, true, { hello: 'world', app: { id: '1234', groups: [{ id: 1},2,3,4,5] }, ids: [1,2,3] }, { app: { name: 'bond', groups: [6, 7, {hello:'world', test: [1,2,3,4, [12,34,45]]}, 9] }, ids: [4,5,6,3] });
 * => "{"hello":"world","app":{"id":"1234","groups":[{"id":1},2,3,4,5,6,7,{"hello":"world","test":[1,2,3,4,[12,34,45]]},9],"name":"bond"},"ids":[1,2,3,4,5,6]}"
 *
 * vs jQuery deep copy
 * jQuery.extend(true, { hello: 'world', app: { id: '1234', groups: [{ id: 1},2,3,4,5] }, ids: [1,2,3] }, { app: { name: 'bond', groups: [6, 7, {hello:'world', test: [1,2,3,4, [12,34,45]]}, 9] }, ids: [4,5,6,3] });
 * => {"hello":"world","app":{"id":"1234","groups":[6,7,{"hello":"world","test":[1,2,3,4,[12,34,45]]},9,5],"name":"bond"},"ids":[4,5,6]}"
 *
 * Shallow copy: (same as everyone else)
 * angular.extend({ hello: [1,2,3,4] },{ hello: [5,6,7,8] })
 * => "{"hello":[5,6,7,8]}"
 */

/*
 * Determine whether an Object is a plain object or not (created using "{}" or "new Object")
 * @param  {Object}  obj Object we want to check
 * @return {Boolean}     True/False result
 */
angular.isPlainObject = function(obj){
 return !(typeof(obj) !== 'object' || obj && obj.nodeType || obj !== null && obj === obj.window || obj && obj.constructor && !Object.prototype.hasOwnProperty.call(obj.constructor.prototype, 'isPrototypeOf'));
};

/**
 * Removes duplicates from an Array
 * @param  {Array}  Array Array to dedup
 * @return {Array}        Array containing only unique values
 */
angular.unique = function(array){
  var a = array.concat();

  for(var i = 0; i < a.length; ++i){
    for(var j = i + 1; j < a.length; ++j){
      if(a[i] === a[j]){
        a.splice(j--, 1);
      }
    }
  }

  return a;
};

/**
 * Merge the contents of two or more objects into the target object
 * @param  {Boolean} deep      If true, the merge becomes recursive (optional)
 * @param  {Object}  target    The object receiving the new properties
 * @param  {Object}  arguments One or more additional objects to merge with the first
 * @return {Object}            The target object with the new contents
 *
 * angular.extend(object, object2)             // shallow copy
 * angular.extend(true, object, object2)       // deep copy
 * angular.extend(true, true, object, object2) // deep copy + dedup arrays
 */
 angular.extend = function(target){
  var i = 1,
      deep = false,
      dedup = false;

  if(typeof(target) === 'boolean'){
    deep = target;
    target = arguments[1] || {};
    i++;

    if(typeof(target) === 'boolean'){
      dedup = target;
      target = arguments[2] || {};
      i++;
    }
  }

  [].slice.call(arguments, i).forEach(function(obj){
    var src, copy, isArray, clone;

    if(obj === target){
      return;
    }

    if(deep && obj instanceof Array){
      target = dedup ? angular.unique(target.concat(obj)) : target.concat(obj);
    }
    else{
      for(var key in obj){
        src = target[key];
        copy = obj[key];

        if(target === copy || src === copy){
          continue;
        }

        if((isArray = copy instanceof Array) || deep && copy && (angular.isPlainObject(copy))){
          if(isArray){
            clone = (src && src instanceof Array) ? src : [];
          }else{
            clone = (src && angular.isPlainObject(src)) ? src : {};
          }

          isArray = false;

          if(dedup){
            target[key] = angular.extend(deep, dedup, clone, copy);
          }else{
            target[key] = angular.extend(deep, clone, copy);
          }
        }
        else if(copy !== undefined){
          target[key] = copy;
        }
      }
    }
  });

  return target;
};