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27 lines
745 B
JavaScript
27 lines
745 B
JavaScript
/**
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* Copyright (c) Facebook, Inc. and its affiliates.
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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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* @flow
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*/
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export let hasBadMapPolyfill;
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if (__DEV__) {
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hasBadMapPolyfill = false;
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try {
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const frozenObject = Object.freeze({});
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const testMap = new Map([[frozenObject, null]]);
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const testSet = new Set([frozenObject]);
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// This is necessary for Rollup to not consider these unused.
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// https://github.com/rollup/rollup/issues/1771
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// TODO: we can remove these if Rollup fixes the bug.
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testMap.set(0, 0);
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testSet.add(0);
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} catch (e) {
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// TODO: Consider warning about bad polyfills
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hasBadMapPolyfill = true;
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}
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}
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