98 lines
2.4 KiB
JavaScript
98 lines
2.4 KiB
JavaScript
//@ts-check
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const createOptions = () => ({
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name: "my-custom-element",
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css: ":host{}",
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html: "",
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ParentClass: HTMLElement,
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observedAttributes: /** @type {string[]}*/ ([]),
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});
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/**
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* WIP: minimal API for custom elements. Do not use!
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* @typedef {ReturnType<typeof createOptions>} Options
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* @param {Partial<Options>} [options]
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*/
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export const createCustomElement = (options) => {
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const {
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name,
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css,
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html,
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observedAttributes: attrs,
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ParentClass,
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} = { ...createOptions(), ...options };
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class CustomClass extends ParentClass {
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static template = document.createElement("template");
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static stylesheet = new CSSStyleSheet();
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constructor(){
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super()
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}
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/**
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* Registers the custom element. If it was already registered, this is a no-op.
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* @param {string} tag
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*/
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static define(tag = name) {
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if (!customElements.get(tag)) {
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customElements.define(tag, this);
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}
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}
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static get observedAttributes() {
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return attrs;
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}
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attributeChangedCallback(property, oldValue, newValue) {
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if (oldValue === newValue) {
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return;
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}
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this[property] = newValue;
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}
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/** @type {AbortController|null} */
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_abortController = null;
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/**
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* If no <template> tag is provided in the page, this uses the parent classe's
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* template and css to create markup
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* Use this in the constructor
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*/
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_autoCreateShadow(){
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if (!this.shadowRoot) {
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const { stylesheet, template } =
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Object.getPrototypeOf(this).constructor;
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this.shadowRoot = this.attachShadow({ mode: "open" });
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this.shadowRoot.adoptedStyleSheets = [stylesheet];
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this.shadowRoot.replaceChildren(template.content.cloneNode(true));
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}
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}
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_getAbortSignal(){
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if(!this._abortController){
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this._abortController = new AbortController()
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}
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return this._abortController.signal
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}
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/**
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* Aborts any event that used the AbortSignal.
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* Use this in the `disconnectedCallback` call
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*/
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_abort(){
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this._abortController && this._abortController.abort();
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}
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}
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const x = new CustomClass();
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CustomClass.template.innerHTML = html;
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CustomClass.stylesheet.replaceSync(css);
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Object.defineProperty(CustomClass, "name", { value: name.replace(/-/s,'') });
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return CustomClass;
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};
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export default createCustomElement |