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- 'use strict';
- const mimicFn = require('mimic-fn');
- const isPromise = require('p-is-promise');
- const mapAgeCleaner = require('map-age-cleaner');
-
- const cacheStore = new WeakMap();
-
- const defaultCacheKey = (...args) => {
- if (args.length === 0) {
- return '__defaultKey';
- }
-
- if (args.length === 1) {
- const [firstArgument] = args;
- if (
- firstArgument === null ||
- firstArgument === undefined ||
- (typeof firstArgument !== 'function' && typeof firstArgument !== 'object')
- ) {
- return firstArgument;
- }
- }
-
- return JSON.stringify(args);
- };
-
- module.exports = (fn, options) => {
- options = Object.assign({
- cacheKey: defaultCacheKey,
- cache: new Map(),
- cachePromiseRejection: false
- }, options);
-
- if (typeof options.maxAge === 'number') {
- mapAgeCleaner(options.cache);
- }
-
- const {cache} = options;
- options.maxAge = options.maxAge || 0;
-
- const setData = (key, data) => {
- cache.set(key, {
- data,
- maxAge: Date.now() + options.maxAge
- });
- };
-
- const memoized = function (...args) {
- const key = options.cacheKey(...args);
-
- if (cache.has(key)) {
- const c = cache.get(key);
-
- return c.data;
- }
-
- const ret = fn.call(this, ...args);
-
- setData(key, ret);
-
- if (isPromise(ret) && options.cachePromiseRejection === false) {
- // Remove rejected promises from cache unless `cachePromiseRejection` is set to `true`
- ret.catch(() => cache.delete(key));
- }
-
- return ret;
- };
-
- mimicFn(memoized, fn);
-
- cacheStore.set(memoized, options.cache);
-
- return memoized;
- };
-
- module.exports.clear = fn => {
- const cache = cacheStore.get(fn);
-
- if (cache && typeof cache.clear === 'function') {
- cache.clear();
- }
- };
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