mirror of
https://github.com/facebook/react.git
synced 2025-11-01 09:12:30 +00:00
Dan Abramov
1cb6199d22
* Consolidate all symbols in a single file This reduces the code duplication as we have quite a few now. * Record sizes
43 lines
1.3 KiB
JavaScript
43 lines
1.3 KiB
JavaScript
/**
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* Copyright (c) 2013-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
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*/
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// The Symbol used to tag the ReactElement-like types. If there is no native Symbol
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// nor polyfill, then a plain number is used for performance.
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const hasSymbol = typeof Symbol === 'function' && Symbol.for;
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export const REACT_ELEMENT_TYPE = hasSymbol
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? Symbol.for('react.element')
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: 0xeac7;
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export const REACT_CALL_TYPE = hasSymbol ? Symbol.for('react.call') : 0xeac8;
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export const REACT_RETURN_TYPE = hasSymbol
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? Symbol.for('react.return')
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: 0xeac9;
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export const REACT_PORTAL_TYPE = hasSymbol
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? Symbol.for('react.portal')
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: 0xeaca;
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export const REACT_FRAGMENT_TYPE = hasSymbol
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? Symbol.for('react.fragment')
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: 0xeacb;
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const MAYBE_ITERATOR_SYMBOL = typeof Symbol === 'function' && Symbol.iterator;
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const FAUX_ITERATOR_SYMBOL = '@@iterator';
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export function getIteratorFn(maybeIterable: ?any): ?() => ?Iterator<*> {
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if (maybeIterable === null || typeof maybeIterable === 'undefined') {
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return null;
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}
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const maybeIterator =
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(MAYBE_ITERATOR_SYMBOL && maybeIterable[MAYBE_ITERATOR_SYMBOL]) ||
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maybeIterable[FAUX_ITERATOR_SYMBOL];
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if (typeof maybeIterator === 'function') {
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return maybeIterator;
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}
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return null;
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}
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