44 lines
1.9 KiB
JavaScript
44 lines
1.9 KiB
JavaScript
/**
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* @license
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* Copyright (c) 2017 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 { isPrimitive } from '../lib/parts.js';
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import { directive, NodePart } from '../lit-html.js';
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// For each part, remember the value that was last rendered to the part by the
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// unsafeHTML directive, and the DocumentFragment that was last set as a value.
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// The DocumentFragment is used as a unique key to check if the last value
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// rendered to the part was with unsafeHTML. If not, we'll always re-render the
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// value passed to unsafeHTML.
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const previousValues = new WeakMap();
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/**
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* Renders the result as HTML, rather than text.
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*
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* Note, this is unsafe to use with any user-provided input that hasn't been
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* sanitized or escaped, as it may lead to cross-site-scripting
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* vulnerabilities.
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*/
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export const unsafeHTML = directive((value) => (part) => {
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if (!(part instanceof NodePart)) {
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throw new Error('unsafeHTML can only be used in text bindings');
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}
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const previousValue = previousValues.get(part);
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if (previousValue !== undefined && isPrimitive(value) &&
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value === previousValue.value && part.value === previousValue.fragment) {
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return;
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}
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const template = document.createElement('template');
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template.innerHTML = value; // innerHTML casts to string internally
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const fragment = document.importNode(template.content, true);
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part.setValue(fragment);
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previousValues.set(part, { value, fragment });
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});
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//# sourceMappingURL=unsafe-html.js.map
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