import baseRest from './_baseRest.js'; import eq from './eq.js'; import isIterateeCall from './_isIterateeCall.js'; import keysIn from './keysIn.js'; /** Used for built-in method references. */ var objectProto = Object.prototype; /** Used to check objects for own properties. */ var hasOwnProperty = objectProto.hasOwnProperty; /** * Assigns own and inherited enumerable string keyed properties of source * objects to the destination object for all destination properties that * resolve to `undefined`. Source objects are applied from left to right. * Once a property is set, additional values of the same property are ignored. * * **Note:** This method mutates `object`. * * @static * @since 0.1.0 * @memberOf _ * @category Object * @param {Object} object The destination object. * @param {...Object} [sources] The source objects. * @returns {Object} Returns `object`. * @see _.defaultsDeep * @example * * _.defaults({ 'a': 1 }, { 'b': 2 }, { 'a': 3 }); * // => { 'a': 1, 'b': 2 } */ var defaults = baseRest(function(object, sources) { object = Object(object); var index = -1; var length = sources.length; var guard = length > 2 ? sources[2] : undefined; if (guard && isIterateeCall(sources[0], sources[1], guard)) { length = 1; } while (++index < length) { var source = sources[index]; var props = keysIn(source); var propsIndex = -1; var propsLength = props.length; while (++propsIndex < propsLength) { var key = props[propsIndex]; var value = object[key]; if (value === undefined || (eq(value, objectProto[key]) && !hasOwnProperty.call(object, key))) { object[key] = source[key]; } } } return object; }); export default defaults;