34 lines
1015 B
JavaScript
34 lines
1015 B
JavaScript
// Takes a root element and a list of ids of shadow host elements. Each id refers to a shadow host
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// inside the previous id's shadow tree.
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function getElementByShadowIds(root, ids) {
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for (var i = 0; ;i++) {
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var host = root.getElementById(ids[i]);
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if (host == null) {
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throw "No element found: i=" + i + " id=" + ids[i] + ". Root was " + root;
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}
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if (i == ids.length - 1) {
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return host;
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}
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root = host.shadowRoot;
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if (root == null) {
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throw "No shadowRoot found: i=" + i + " id=" + ids[i] + ". Host was " + host;
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}
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}
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}
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// Installs a mininal custom element based on this template.
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function installCustomElement(element_name, template_id) {
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ceClass = class extends HTMLElement {
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constructor() {
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super();
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var template = document
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.getElementById(template_id)
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.content;
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this
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.attachShadow({mode: 'open'})
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.appendChild(template.cloneNode(true));
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}
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};
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window.customElements.define(element_name, ceClass);
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}
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