Add custom HTML Elements for icons/SVG loading

module/apps/elements/Icon.mjs

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+import { TafSVGLoader } from "./svgLoader.mjs";
+
+/**
+Attributes:
+@property {string} name - The name of the icon, takes precedence over the path
+@property {string} path - The path of the icon file
+*/
+export class TafIcon extends TafSVGLoader {
+	static elementName = `taf-icon`;
+	static _stylePath = `icon.css`;
+};

module/apps/elements/StyledShadowElement.mjs

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+import { filePath } from "../../consts.mjs";
+
+/**
+ * @param {HTMLElement} Base
+ */
+export function StyledShadowElement(Base) {
+	return class extends Base {
+		/**
+		 * The path to the CSS that is loaded
+		 * @type {string}
+		 */
+		static _stylePath;
+
+		/**
+		 * The stringified CSS to use
+		 * @type {Map<string, string>}
+		 */
+		static _styles = new Map();
+
+		/**
+		 * The HTML element of the stylesheet
+		 * @type {HTMLStyleElement}
+		 */
+		_style;
+
+		/** @type {ShadowRoot} */
+		_shadow;
+
+		constructor() {
+			super();
+
+			this._shadow = this.attachShadow({ mode: `open` });
+			this._style = document.createElement(`style`);
+			this._shadow.appendChild(this._style);
+		};
+
+		#mounted = false;
+		connectedCallback() {
+			if (this.#mounted) { return };
+
+			this._getStyles();
+
+			this.#mounted = true;
+		};
+
+		disconnectedCallback() {
+			if (!this.#mounted) { return };
+			this.#mounted = false;
+		};
+
+		_getStyles() {
+			// TODO: Cache the CSS content in a more sane way that doesn't break
+			const stylePath = this.constructor._stylePath;
+			if (this.constructor._styles.has(stylePath)) {
+				this._style.innerHTML = this.constructor._styles.get(stylePath);
+			} else {
+				fetch(filePath(`styles/components/${stylePath}`))
+					.then(r => r.text())
+					.then(t => {
+						this.constructor._styles.set(stylePath, t);
+						this._style.innerHTML = t;
+					});
+			}
+		};
+	};
+};

module/apps/elements/_index.mjs

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+import { Logger } from "../../utils/Logger.mjs";
+import { TafIcon } from "./Icon.mjs";
+import { TafSVGLoader } from "./svgLoader.mjs";
+
+const components = [
+	TafSVGLoader,
+	TafIcon,
+];
+
+export function registerCustomComponents() {
+	(CONFIG.CACHE ??= {}).componentListeners ??= [];
+	for (const component of components) {
+		if (!window.customElements.get(component.elementName)) {
+			Logger.debug(`Registering component "${component.elementName}"`);
+			window.customElements.define(
+				component.elementName,
+				component,
+			);
+			if (component.formAssociated) {
+				CONFIG.CACHE.componentListeners.push(component.elementName);
+			}
+		};
+	}
+};

module/apps/elements/svgLoader.mjs

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+import { filePath } from "../../consts.mjs";
+import { Logger } from "../../utils/Logger.mjs";
+import { StyledShadowElement } from "./StyledShadowElement.mjs";
+
+/**
+Attributes:
+@property {string} name - The name of the icon, takes precedence over the path
+@property {string} path - The path of the icon file
+*/
+export class TafSVGLoader extends StyledShadowElement(HTMLElement) {
+	static elementName = `taf-svg`;
+	static formAssociated = false;
+
+	/* Stuff for the mixin to use */
+	static _stylePath = `svg-loader.css`;
+
+
+	static _cache = new Map();
+	#container;
+	/** @type {null | string} */
+	_name;
+	/** @type {null | string} */
+	_path;
+
+	constructor() {
+		super();
+
+		this.#container = document.createElement(`div`);
+		this._shadow.appendChild(this.#container);
+	};
+
+	_mounted = false;
+	async connectedCallback() {
+		super.connectedCallback();
+		if (this._mounted) { return };
+
+		this._name = this.getAttribute(`name`);
+		this._path = this.getAttribute(`path`);
+
+		/*
+		This converts all of the double-dash prefixed properties on the element to
+		CSS variables so that they don't all need to be provided by doing style=""
+		*/
+		for (const attrVar of this.attributes) {
+			if (attrVar.name?.startsWith(`var:`)) {
+				const prop = attrVar.name.replace(`var:`, ``);
+				this.style.setProperty(`--` + prop, attrVar.value);
+			};
+		};
+
+		/*
+		Try to retrieve the icon if it isn't present, try the path then default to
+		the slot content, as then we can have a default per-icon usage
+		*/
+		let content;
+		if (this._name) {
+			content = await this.#getIcon(filePath(`assets/${this._name}.svg`));
+		};
+
+		if (this._path && !content) {
+			content = await this.#getIcon(this._path);
+		};
+
+		if (content) {
+			this.#container.appendChild(content.cloneNode(true));
+		};
+
+		this._mounted = true;
+	};
+
+	disconnectedCallback() {
+		super.disconnectedCallback();
+		if (!this._mounted) { return };
+
+		this._mounted = false;
+	};
+
+	async #getIcon(path) {
+		// Cache hit!
+		if (this.constructor._cache.has(path)) {
+			Logger.debug(`Image ${path} cache hit`);
+			return this.constructor._cache.get(path);
+		};
+
+		const r = await fetch(path);
+		switch (r.status) {
+			case 200:
+			case 201:
+				break;
+			default:
+				Logger.error(`Failed to fetch icon: ${path}`);
+				return;
+		};
+
+		Logger.debug(`Adding image ${path} to the cache`);
+		const svg = this.#parseSVG(await r.text());
+		this.constructor._cache.set(path, svg);
+		return svg;
+	};
+
+	/** Takes an SVG string and returns it as a DOM node */
+	#parseSVG(content) {
+		const temp = document.createElement(`div`);
+		temp.innerHTML = content;
+		return temp.querySelector(`svg`);
+	};
+};