41 lines
1.2 KiB
JavaScript
41 lines
1.2 KiB
JavaScript
import { attributesWithLists } from './collapseAttributeWhitespace.mjs';
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/** Deduplicate values inside list-like attributes (e.g. class, rel) */
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export function onAttrs() {
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return (attrs) => {
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const newAttrs = attrs;
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Object.keys(attrs).forEach(attrName => {
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if (! attributesWithLists.has(attrName)) {
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return;
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}
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if (typeof attrs[attrName] !== 'string') {
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return;
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}
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const attrValues = attrs[attrName].split(/\s/);
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const uniqeAttrValues = new Set();
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const deduplicatedAttrValues = [];
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attrValues.forEach((attrValue) => {
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if (! attrValue) {
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// Keep whitespaces
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deduplicatedAttrValues.push('');
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return;
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}
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if (uniqeAttrValues.has(attrValue)) {
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return;
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}
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deduplicatedAttrValues.push(attrValue);
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uniqeAttrValues.add(attrValue);
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});
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newAttrs[attrName] = deduplicatedAttrValues.join(' ');
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});
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return newAttrs;
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};
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}
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