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