56 lines
1.0 KiB
JavaScript
56 lines
1.0 KiB
JavaScript
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'use strict';
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const mimicFn = require('mimic-fn');
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const cacheStore = new WeakMap();
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const defaultCacheKey = function (x) {
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if (arguments.length === 1 && (x === null || x === undefined || (typeof x !== 'function' && typeof x !== 'object'))) {
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return x;
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}
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return JSON.stringify(arguments);
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};
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module.exports = (fn, opts) => {
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opts = Object.assign({
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cacheKey: defaultCacheKey,
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cache: new Map()
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}, opts);
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const memoized = function () {
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const cache = cacheStore.get(memoized);
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const key = opts.cacheKey.apply(null, arguments);
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if (cache.has(key)) {
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const c = cache.get(key);
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if (typeof opts.maxAge !== 'number' || Date.now() < c.maxAge) {
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return c.data;
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}
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}
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const ret = fn.apply(null, arguments);
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cache.set(key, {
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data: ret,
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maxAge: Date.now() + (opts.maxAge || 0)
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});
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return ret;
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};
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mimicFn(memoized, fn);
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cacheStore.set(memoized, opts.cache);
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return memoized;
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};
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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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