Make a mixin for loading a stylesheet for components, including HMR auto-update support (only in devMode)

module/components/icon.mjs

@@ -1,34 +1,39 @@
+import { StyledShadowElement } from "./mixins/Styles.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 DotDungeonIcon extends HTMLElement {
+export class DotDungeonIcon extends StyledShadowElement(HTMLElement) {
 	static elementName = `dd-icon`;
 	static formAssociated = false;
 
-	#shadow;
+	/* Stuff for the mixin to use */
+	static _stylePath = `v3/components/icon.css`;
+
 
-	static #styles = ``;
 	static _cache = new Map();
-	#style;
 	#container;
 	/** @type {null | string} */
 	_name;
 	/** @type {null | string} */
 	_path;
 
+	/* Stored IDs for all of the hooks that are in this component */
+	#svgHmr;
+
 	constructor() {
 		super();
-		this.#shadow = this.attachShadow({ mode: `open`, delegatesFocus: true });
+		// this._shadow = this.attachShadow({ mode: `open`, delegatesFocus: true });
-		if (DotDungeonIcon.#styles) this.#embedStyles();
 
 		this.#container = document.createElement(`div`);
-		this.#shadow.appendChild(this.#container);
+		this._shadow.appendChild(this.#container);
 	};
 
 	_mounted = false;
 	async connectedCallback() {
+		super.connectedCallback();
 		if (this._mounted) return;
 
 		this._name = this.getAttribute(`name`);
@@ -45,18 +50,6 @@ export class DotDungeonIcon extends HTMLElement {
 			};
 		};
 
-		/*
-		Style fetching if we haven't gotten them yet
-		*/
-		if (!DotDungeonIcon.#styles) {
-			fetch(`./systems/dotdungeon/.styles/v3/components/icon.css`)
-			.then(r => r.text())
-			.then(t => {
-				DotDungeonIcon.#styles = t;
-				this.#embedStyles();
-			});
-		};
-
 		/*
 		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
@@ -78,28 +71,33 @@ export class DotDungeonIcon extends HTMLElement {
 		This is so that when we get an HMR event from Foundry we can appropriately
 		handle it using our logic to update the component and the icon cache.
 		*/
-		Hooks.on(`dd-hmr:svg`, (iconName, data) => {
+		if (game.settings.get(`dotdungeon`, `devMode`)) {
+			this.#svgHmr = Hooks.on(`dd-hmr:svg`, (iconName, data) => {
 				if (this._name === iconName || this._path?.endsWith(data.path)) {
 					const svg = this.#parseSVG(data.content);
-				DotDungeonIcon._cache.set(iconName, svg);
+					this.constructor._cache.set(iconName, svg);
 					this.#container.replaceChildren(svg.cloneNode(true));
 				};
 			});
+		};
 
 		this._mounted = true;
 	};
 
-	#embedStyles() {
+	disconnectedCallback() {
-		this.#style = document.createElement(`style`);
+		super.disconnectedCallback();
-		this.#style.innerHTML = DotDungeonIcon.#styles;
+		if (!this._mounted) return;
-		this.#shadow.appendChild(this.#style);
+
+		Hooks.off(`dd-hmr:svg`, this.#svgHmr);
+
+		this._mounted = false;
 	};
 
 	async #getIcon(path) {
 		// Cache hit!
-		if (DotDungeonIcon._cache.has(path)) {
+		if (this.constructor._cache.has(path)) {
 			console.debug(`.dungeon | Icon ${path} cache hit`);
-			return DotDungeonIcon._cache.get(path);
+			return this.constructor._cache.get(path);
 		};
 
 		const r = await fetch(path);
@@ -114,7 +112,7 @@ export class DotDungeonIcon extends HTMLElement {
 
 		console.debug(`.dungeon | Adding icon ${path} to the cache`);
 		const svg = this.#parseSVG(await r.text());
-		DotDungeonIcon._cache.set(path, svg);
+		this.constructor._cache.set(path, svg);
 		return svg;
 	};
 
@@ -123,5 +121,5 @@ export class DotDungeonIcon extends HTMLElement {
 		const temp = document.createElement(`div`);
 		temp.innerHTML = content;
 		return temp.querySelector(`svg`);
-	}
+	};
 };

module/components/incrementer.mjs

@@ -1,4 +1,5 @@
 import { DotDungeonIcon } from "./icon.mjs";
+import { StyledShadowElement } from "./mixins/Styles.mjs";
 
 /**
 Attributes:
@@ -13,15 +14,14 @@ Styling:
 - `--height`: Controls the height of the element + the width of the buttons (default: 1.25rem)
 - `--width`: Controls the width of the number input (default 50px)
 */
-export class DotDungeonIncrementer extends HTMLElement {
+export class DotDungeonIncrementer extends StyledShadowElement(HTMLElement) {
 	static elementName = `dd-incrementer`;
 	static formAssociated = true;
 
-	static #styles = ``;
+	static _stylePath = `v3/components/incrementer.css`;
+
 	_internals;
-	_shadow;
 	#input;
-	#style;
 
 	_min;
 	_max;
@@ -30,8 +30,6 @@ export class DotDungeonIncrementer extends HTMLElement {
 
 	constructor() {
 		super();
-		this._shadow = this.attachShadow({ mode: `open`, delegatesFocus: true });
-		if (DotDungeonIncrementer.#styles) this.#embedStyles();
 
 		// Form internals
 		this._internals = this.attachInternals();
@@ -61,6 +59,7 @@ export class DotDungeonIncrementer extends HTMLElement {
 	}
 
 	connectedCallback() {
+		super.connectedCallback();
 		this.replaceChildren();
 
 		// Attribute parsing / registration
@@ -119,21 +118,6 @@ export class DotDungeonIncrementer extends HTMLElement {
 				this.style.setProperty(`--` + prop, attrVar.value);
 			};
 		};
-
-		if (!DotDungeonIncrementer.#styles) {
-			fetch(`./systems/dotdungeon/.styles/v3/components/incrementer.css`)
-			.then(r => r.text())
-			.then(t => {
-				DotDungeonIncrementer.#styles = t;
-				this.#embedStyles();
-			});
-		};
-	};
-
-	#embedStyles() {
-		this.#style = document.createElement(`style`);
-		this.#style.innerHTML = DotDungeonIncrementer.#styles;
-		this._shadow.appendChild(this.#style);
 	};
 
 	#updateValue() {

module/components/mixins/Styles.mjs

@@ -0,0 +1,80 @@
+/**
+ * @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 {string}
+		 */
+		static _styles;
+
+		/**
+		 * The HTML element of the stylesheet
+		 * @type {HTMLStyleElement}
+		 */
+		_style;
+
+		/** @type {ShadowRoot} */
+		_shadow;
+
+		/**
+		 * The hook ID for this element's CSS hot reload
+		 * @type {number}
+		 */
+		#cssHmr;
+
+		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();
+
+			if (game.settings.get(`dotdungeon`, `devMode`)) {
+				this.#cssHmr = Hooks.on(`dd-hmr:css`, (data) => {
+					if (data.path.endsWith(this.constructor._stylePath)) {
+						this._style.innerHTML = data.content;
+					};
+				});
+			};
+
+			this.#mounted = true;
+		};
+
+		disconnectedCallback() {
+			if (!this.#mounted) return;
+			if (this.#cssHmr != null) {
+				Hooks.off(`dd-hmr:css`, this.#cssHmr);
+				this.#cssHmr = null;
+			};
+			this.#mounted = false;
+		};
+
+		_getStyles() {
+			if (this.constructor._styles) {
+				this._style.innerHTML = this.constructor._styles;
+			} else {
+				fetch(`./systems/dotdungeon/.styles/${this.constructor._stylePath}`)
+				.then(r => r.text())
+				.then(t => {
+					this.constructor._styles = t;
+					this._style.innerHTML = t;
+				});
+			}
+		};
+	};
+};

module/hooks/hotReload.mjs

@@ -35,6 +35,10 @@ const loaders = {
 	},
 	js() {window.location.reload()},
 	mjs() {window.location.reload()},
+	css(data) {
+		console.debug(`.dungeon | Hot-reloading CSS: ${data.path}`);
+		Hooks.call(`dd-hmr:css`, data);
+	},
 };
 
 Hooks.on(`hotReload`, async (data) => {