42 lines
No EOL
1.7 KiB
JavaScript
42 lines
No EOL
1.7 KiB
JavaScript
/**
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* Loads all stylesheets from the given root element into the document.
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* @returns an array of promises that resolve when each stylesheet is loaded
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* @param document Document to load stylesheets into
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* @param root Document or ShadowRoot to load stylesheets from
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*/
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export function loadStyleSheets(document, root) {
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const stylesheetLoadPromises = [];
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const headStyleElements = root.querySelectorAll("style, link[rel='stylesheet']");
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for (let i = 0; i < headStyleElements.length; i += 1) {
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const node = headStyleElements[i];
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if (node.tagName === 'STYLE') {
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const newHeadStyleElements = document.createElement(node.tagName);
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const sheet = node.sheet;
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if (sheet) {
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let styleCSS = '';
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for (let j = 0; j < sheet.cssRules.length; j += 1) {
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if (typeof sheet.cssRules[j].cssText === 'string') {
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styleCSS += `${sheet.cssRules[j].cssText}\r\n`;
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}
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}
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newHeadStyleElements.appendChild(document.createTextNode(styleCSS));
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document.head.appendChild(newHeadStyleElements);
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}
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} else if (node.getAttribute('href')) {
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// If `href` tag is empty, avoid loading these links
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const newHeadStyleElements = document.createElement(node.tagName);
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for (let j = 0; j < node.attributes.length; j += 1) {
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const attr = node.attributes[j];
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if (attr) {
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newHeadStyleElements.setAttribute(attr.nodeName, attr.nodeValue || '');
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}
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}
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stylesheetLoadPromises.push(new Promise(resolve => {
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newHeadStyleElements.addEventListener('load', () => resolve());
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}));
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document.head.appendChild(newHeadStyleElements);
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}
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}
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return stylesheetLoadPromises;
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} |