Permalink
| /** | |
| * Creates a function that memoizes the result of `func`. If `resolver` is | |
| * provided, it determines the cache key for storing the result based on the | |
| * arguments provided to the memoized function. By default, the first argument | |
| * provided to the memoized function is used as the map cache key. The `func` | |
| * is invoked with the `this` binding of the memoized function. | |
| * | |
| * **Note:** The cache is exposed as the `cache` property on the memoized | |
| * function. Its creation may be customized by replacing the `memoize.Cache` | |
| * constructor with one whose instances implement the | |
| * [`Map`](http://ecma-international.org/ecma-262/7.0/#sec-properties-of-the-map-prototype-object) | |
| * method interface of `clear`, `delete`, `get`, `has`, and `set`. | |
| * | |
| * @since 0.1.0 | |
| * @category Function | |
| * @param {Function} func The function to have its output memoized. | |
| * @param {Function} [resolver] The function to resolve the cache key. | |
| * @returns {Function} Returns the new memoized function. | |
| * @example | |
| * | |
| * const object = { 'a': 1, 'b': 2 } | |
| * const other = { 'c': 3, 'd': 4 } | |
| * | |
| * const values = memoize(values) | |
| * values(object) | |
| * // => [1, 2] | |
| * | |
| * values(other) | |
| * // => [3, 4] | |
| * | |
| * object.a = 2 | |
| * values(object) | |
| * // => [1, 2] | |
| * | |
| * // Modify the result cache. | |
| * values.cache.set(object, ['a', 'b']) | |
| * values(object) | |
| * // => ['a', 'b'] | |
| * | |
| * // Replace `memoize.Cache`. | |
| * memoize.Cache = WeakMap | |
| */ | |
| function memoize(func, resolver) { | |
| if (typeof func !== 'function' || (resolver != null && typeof resolver !== 'function')) { | |
| throw new TypeError('Expected a function') | |
| } | |
| const memoized = function(...args) { | |
| const key = resolver ? resolver.apply(this, args) : args[0] | |
| const cache = memoized.cache | |
| if (cache.has(key)) { | |
| return cache.get(key) | |
| } | |
| const result = func.apply(this, args) | |
| memoized.cache = cache.set(key, result) || cache | |
| return result | |
| } | |
| memoized.cache = new (memoize.Cache || Map) | |
| return memoized | |
| } | |
| memoize.Cache = Map | |
| export default memoize |