168 lines
4.6 KiB
JavaScript
168 lines
4.6 KiB
JavaScript
/**
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* lodash 3.0.4 (Custom Build) <https://lodash.com/>
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* Build: `lodash modern modularize exports="npm" -o ./`
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* Copyright 2012-2015 The Dojo Foundation <http://dojofoundation.org/>
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* Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
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* Copyright 2009-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
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* Available under MIT license <https://lodash.com/license>
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*/
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/** Used as the `TypeError` message for "Functions" methods. */
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var FUNC_ERROR_TEXT = 'Expected a function';
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/** Used for native 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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* Creates a cache object to store key/value pairs.
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*
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* @private
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* @static
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* @name Cache
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* @memberOf _.memoize
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*/
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function MapCache() {
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this.__data__ = {};
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}
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/**
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* Removes `key` and its value from the cache.
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*
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* @private
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* @name delete
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* @memberOf _.memoize.Cache
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* @param {string} key The key of the value to remove.
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* @returns {boolean} Returns `true` if the entry was removed successfully, else `false`.
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*/
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function mapDelete(key) {
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return this.has(key) && delete this.__data__[key];
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}
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/**
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* Gets the cached value for `key`.
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*
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* @private
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* @name get
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* @memberOf _.memoize.Cache
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* @param {string} key The key of the value to get.
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* @returns {*} Returns the cached value.
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*/
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function mapGet(key) {
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return key == '__proto__' ? undefined : this.__data__[key];
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}
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/**
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* Checks if a cached value for `key` exists.
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*
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* @private
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* @name has
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* @memberOf _.memoize.Cache
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* @param {string} key The key of the entry to check.
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* @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
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*/
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function mapHas(key) {
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return key != '__proto__' && hasOwnProperty.call(this.__data__, key);
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}
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/**
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* Sets `value` to `key` of the cache.
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*
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* @private
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* @name set
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* @memberOf _.memoize.Cache
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* @param {string} key The key of the value to cache.
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* @param {*} value The value to cache.
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* @returns {Object} Returns the cache object.
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*/
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function mapSet(key, value) {
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if (key != '__proto__') {
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this.__data__[key] = value;
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}
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return this;
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}
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/**
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* Creates a function that memoizes the result of `func`. If `resolver` is
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* provided it determines the cache key for storing the result based on the
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* arguments provided to the memoized function. By default, the first argument
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* provided to the memoized function is coerced to a string and used as the
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* cache key. The `func` is invoked with the `this` binding of the memoized
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* function.
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*
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* **Note:** The cache is exposed as the `cache` property on the memoized
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* function. Its creation may be customized by replacing the `_.memoize.Cache`
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* constructor with one whose instances implement the [`Map`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-properties-of-the-map-prototype-object)
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* method interface of `get`, `has`, and `set`.
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*
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* @static
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* @memberOf _
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* @category Function
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* @param {Function} func The function to have its output memoized.
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* @param {Function} [resolver] The function to resolve the cache key.
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* @returns {Function} Returns the new memoizing function.
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* @example
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*
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* var upperCase = _.memoize(function(string) {
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* return string.toUpperCase();
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* });
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*
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* upperCase('fred');
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* // => 'FRED'
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*
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* // modifying the result cache
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* upperCase.cache.set('fred', 'BARNEY');
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* upperCase('fred');
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* // => 'BARNEY'
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*
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* // replacing `_.memoize.Cache`
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* var object = { 'user': 'fred' };
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* var other = { 'user': 'barney' };
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* var identity = _.memoize(_.identity);
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*
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* identity(object);
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* // => { 'user': 'fred' }
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* identity(other);
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* // => { 'user': 'fred' }
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*
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* _.memoize.Cache = WeakMap;
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* var identity = _.memoize(_.identity);
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*
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* identity(object);
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* // => { 'user': 'fred' }
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* identity(other);
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* // => { 'user': 'barney' }
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*/
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function memoize(func, resolver) {
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if (typeof func != 'function' || (resolver && typeof resolver != 'function')) {
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throw new TypeError(FUNC_ERROR_TEXT);
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}
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var memoized = function() {
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var args = arguments,
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key = resolver ? resolver.apply(this, args) : args[0],
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cache = memoized.cache;
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if (cache.has(key)) {
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return cache.get(key);
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}
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var result = func.apply(this, args);
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memoized.cache = cache.set(key, result);
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return result;
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};
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memoized.cache = new memoize.Cache;
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return memoized;
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}
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// Add functions to the `Map` cache.
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MapCache.prototype['delete'] = mapDelete;
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MapCache.prototype.get = mapGet;
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MapCache.prototype.has = mapHas;
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MapCache.prototype.set = mapSet;
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// Assign cache to `_.memoize`.
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memoize.Cache = MapCache;
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module.exports = memoize;
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