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49 lines
1.4 KiB
JavaScript
49 lines
1.4 KiB
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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import type {ReactEventResponder, ReactEventComponent} from 'shared/ReactTypes';
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import {REACT_EVENT_COMPONENT_TYPE} from 'shared/ReactSymbols';
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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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export default function createEventComponent<T, E, C>(
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responder: ReactEventResponder<T, E, C>,
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): ReactEventComponent<T, E, C> {
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// We use responder as a Map key later on. When we have a bad
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// polyfill, then we can't use it as a key as the polyfill tries
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// to add a property to the object.
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if (__DEV__ && !hasBadMapPolyfill) {
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Object.freeze(responder);
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}
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const eventComponent = {
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$$typeof: REACT_EVENT_COMPONENT_TYPE,
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responder: responder,
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};
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if (__DEV__) {
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Object.freeze(eventComponent);
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}
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return eventComponent;
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}
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