lodash/mixin.js

define(['./_arrayEach', './_arrayPush', './_baseFunctions', './_copyArray', './isFunction', './isObject', './keys'], function(arrayEach, arrayPush, baseFunctions, copyArray, isFunction, isObject, keys) {

  /**
   * Adds all own enumerable function properties of a source object to the
   * destination object. If `object` is a function then methods are added to
   * its prototype as well.
   *
   * **Note:** Use `_.runInContext` to create a pristine `lodash` function to
   * avoid conflicts caused by modifying the original.
   *
   * @static
   * @memberOf _
   * @category Util
   * @param {Function|Object} [object=lodash] The destination object.
   * @param {Object} source The object of functions to add.
   * @param {Object} [options] The options object.
   * @param {boolean} [options.chain=true] Specify whether the functions added
   *  are chainable.
   * @returns {Function|Object} Returns `object`.
   * @example
   *
   * function vowels(string) {
   *   return _.filter(string, function(v) {
   *     return /[aeiou]/i.test(v);
   *   });
   * }
   *
   * _.mixin({ 'vowels': vowels });
   * _.vowels('fred');
   * // => ['e']
   *
   * _('fred').vowels().value();
   * // => ['e']
   *
   * _.mixin({ 'vowels': vowels }, { 'chain': false });
   * _('fred').vowels();
   * // => ['e']
   */
  function mixin(object, source, options) {
    var props = keys(source),
        methodNames = baseFunctions(source, props);

    var chain = (isObject(options) && 'chain' in options) ? options.chain : true,
        isFunc = isFunction(object);

    arrayEach(methodNames, function(methodName) {
      var func = source[methodName];
      object[methodName] = func;
      if (isFunc) {
        object.prototype[methodName] = function() {
          var chainAll = this.__chain__;
          if (chain || chainAll) {
            var result = object(this.__wrapped__),
                actions = result.__actions__ = copyArray(this.__actions__);

            actions.push({ 'func': func, 'args': arguments, 'thisArg': object });
            result.__chain__ = chainAll;
            return result;
          }
          return func.apply(object, arrayPush([this.value()], arguments));
        };
      }
    });

    return object;
  }

  return mixin;
});