75 lines
1.5 KiB
JavaScript
75 lines
1.5 KiB
JavaScript
'use strict';
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const mimicFn = require('mimic-fn');
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const isPromise = require('p-is-promise');
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const mapAgeCleaner = require('map-age-cleaner');
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const cacheStore = new WeakMap();
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const defaultCacheKey = (...arguments_) => {
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if (arguments_.length === 0) {
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return '__defaultKey';
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}
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if (arguments_.length === 1) {
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const [firstArgument] = arguments_;
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const isObject = typeof firstArgument === 'object' && firstArgument !== null;
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const isPrimitive = !isObject;
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if (isPrimitive) {
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return firstArgument;
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}
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}
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return JSON.stringify(arguments_);
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};
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const mem = (fn, {
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cacheKey = defaultCacheKey,
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cache = new Map(),
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cachePromiseRejection = true,
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maxAge
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} = {}) => {
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if (typeof maxAge === 'number') {
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mapAgeCleaner(cache);
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}
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const memoized = function (...arguments_) {
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const key = cacheKey(...arguments_);
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if (cache.has(key)) {
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return cache.get(key).data;
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}
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const cacheItem = fn.apply(this, arguments_);
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cache.set(key, {
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data: cacheItem,
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maxAge: maxAge ? Date.now() + maxAge : Infinity
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});
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if (isPromise(cacheItem) && cachePromiseRejection === false) {
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cacheItem.catch(() => cache.delete(key));
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}
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return cacheItem;
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};
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try {
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// The below call will throw in some host environments
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// See https://github.com/sindresorhus/mimic-fn/issues/10
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mimicFn(memoized, fn);
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} catch (_) {}
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cacheStore.set(memoized, cache);
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return memoized;
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};
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module.exports = mem;
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module.exports.clear = fn => {
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const cache = cacheStore.get(fn);
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if (cache && typeof cache.clear === 'function') {
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cache.clear();
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}
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};
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