lodash/lodash.defaultsdeep/index.js

/**
 * lodash 3.10.0 (Custom Build) <https://lodash.com/>
 * Build: `lodash modern modularize exports="npm" -o ./`
 * Copyright 2012-2015 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <https://lodash.com/license>
 */
var merge = require('lodash.merge'),
    restParam = require('lodash.restparam');

/**
 * Creates a `_.defaults` or `_.defaultsDeep` function.
 *
 * @private
 * @param {Function} assigner The function to assign values.
 * @param {Function} customizer The function to customize assigned values.
 * @returns {Function} Returns the new defaults function.
 */
function createDefaults(assigner, customizer) {
  return restParam(function(args) {
    var object = args[0];
    if (object == null) {
      return object;
    }
    args.push(customizer);
    return assigner.apply(undefined, args);
  });
}

/**
 * Used by `_.defaultsDeep` to customize its `_.merge` use.
 *
 * @private
 * @param {*} objectValue The destination object property value.
 * @param {*} sourceValue The source object property value.
 * @returns {*} Returns the value to assign to the destination object.
 */
function mergeDefaults(objectValue, sourceValue) {
  return objectValue === undefined ? sourceValue : merge(objectValue, sourceValue, mergeDefaults);
}

/**
 * This method is like `_.defaults` except that it recursively assigns
 * default properties.
 *
 * **Note:** This method mutates `object`.
 *
 * @static
 * @memberOf _
 * @category Object
 * @param {Object} object The destination object.
 * @param {...Object} [sources] The source objects.
 * @returns {Object} Returns `object`.
 * @example
 *
 * _.defaultsDeep({ 'user': { 'name': 'barney' } }, { 'user': { 'name': 'fred', 'age': 36 } });
 * // => { 'user': { 'name': 'barney', 'age': 36 } }
 *
 */
var defaultsDeep = createDefaults(merge, mergeDefaults);

module.exports = defaultsDeep;