32 lines
1.1 KiB
JavaScript
32 lines
1.1 KiB
JavaScript
/**
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* @license
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* Copyright (c) 2018 The Polymer Project Authors. All rights reserved.
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* This code may only be used under the BSD style license found at
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* http://polymer.github.io/LICENSE.txt
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* The complete set of authors may be found at
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* http://polymer.github.io/AUTHORS.txt
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* The complete set of contributors may be found at
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* http://polymer.github.io/CONTRIBUTORS.txt
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* Code distributed by Google as part of the polymer project is also
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* subject to an additional IP rights grant found at
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* http://polymer.github.io/PATENTS.txt
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*/
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import { AttributePart, directive } from '../lit-html.js';
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/**
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* For AttributeParts, sets the attribute if the value is defined and removes
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* the attribute if the value is undefined.
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*
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* For other part types, this directive is a no-op.
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*/
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export const ifDefined = directive((value) => (part) => {
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if (value === undefined && part instanceof AttributePart) {
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if (value !== part.value) {
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const name = part.committer.name;
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part.committer.element.removeAttribute(name);
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}
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}
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else {
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part.setValue(value);
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}
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});
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//# sourceMappingURL=if-defined.js.map
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