45 lines
999 B
Plaintext
45 lines
999 B
Plaintext
/**
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* Copyright (c) 2017-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @flow strict
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*/
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/**
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* Memoizes the provided three-argument function.
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*/
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export default function memoize3<T: (a1: any, a2: any, a3: any) => any>(
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fn: T,
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): T {
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let cache0;
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function memoized(a1, a2, a3) {
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if (!cache0) {
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cache0 = new WeakMap();
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}
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let cache1 = cache0.get(a1);
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let cache2;
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if (cache1) {
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cache2 = cache1.get(a2);
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if (cache2) {
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const cachedValue = cache2.get(a3);
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if (cachedValue !== undefined) {
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return cachedValue;
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}
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}
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} else {
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cache1 = new WeakMap();
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cache0.set(a1, cache1);
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}
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if (!cache2) {
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cache2 = new WeakMap();
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cache1.set(a2, cache2);
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}
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const newValue = fn.apply(this, arguments);
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cache2.set(a3, newValue);
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return newValue;
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}
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return (memoized: any);
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}
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