52 lines
1.3 KiB
JavaScript
52 lines
1.3 KiB
JavaScript
/**
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* Copyright (c) Nicolas Gallagher.
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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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*
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*
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*/
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import { canUseDOM } from 'fbjs/lib/ExecutionEnvironment';
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function getQuery() {
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return canUseDOM && window.matchMedia != null ? window.matchMedia('(prefers-color-scheme: dark)') : null;
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}
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var query = getQuery();
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var listenerMapping = new WeakMap();
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var Appearance = {
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getColorScheme: function getColorScheme() {
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return query && query.matches ? 'dark' : 'light';
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},
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addChangeListener: function addChangeListener(listener) {
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var mappedListener = listenerMapping.get(listener);
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if (!mappedListener) {
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mappedListener = function mappedListener(_ref) {
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var matches = _ref.matches;
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listener({
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colorScheme: matches ? 'dark' : 'light'
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});
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};
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listenerMapping.set(listener, mappedListener);
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}
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if (query) {
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query.addListener(mappedListener);
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}
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},
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removeChangeListener: function removeChangeListener(listener) {
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var mappedListener = listenerMapping.get(listener);
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if (mappedListener) {
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if (query) {
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query.removeListener(mappedListener);
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}
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listenerMapping.delete(listener);
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}
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}
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};
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export default Appearance; |