render.js

@@ -1,19 +1,13 @@
 // Keep a referee alive until a referrer is collected
 const weakReferences = new WeakMap()
-
-/** Keeps the referenced value alive until the referrer is collected
- * @param {Object} referrer
- * @param {Object} reference
- */
 const untilDeathDoThemPart = (referrer, reference) => {
 	if (!weakReferences.has(referrer)) weakReferences.set(referrer, new Set())
 	weakReferences.get(referrer).add(reference)
 }
 
-/** Like AbortController, but resets after each abort */
+// Like AbortController, but resets after each abort
 class MultiAbortController {
 	#controller = new AbortController()
-	/** @return {AbortSignal} */
 	get signal() { return this.#controller.signal }
 	abort() { this.#controller.abort(); this.#controller = new AbortController() }
 }
@@ -27,50 +21,242 @@ export const empty = Symbol("Explicit empty argument for Skooma")
 */
 const snakeToCSS = key => key.replace(/^[A-Z]/, a => "-"+a).replace(/[A-Z]/g, a => '-'+a.toLowerCase())
 
+/**
+* @param {CSSStyleDeclaration} style The style property of a node
+* @param {object} rules A map of snake case property names to css values
+*/
+const insertStyles = (style, rules) => {
+	for (const [key, value] of Object.entries(rules))
+		if (typeof value == "undefined")
+			style.removeProperty(snakeToCSS(key))
+	else
+		style.setProperty(snakeToCSS(key), value.toString())
+}
+
 /** @typedef SpecialAttributeDescriptor
 * @type {object}
- * @property {function(Node):void} [get]
- * @property {function(Node,any):void} [set]
- * @property {function(Node,function(any):void):void} [subscribe]
- * @property {function(Node):boolean} [filter]
+* @property {function(this:any):void} [get]
+* @property {function(this:any,any):void} [set]
+* @property {function(this:any,function():void):void} [hook]
 */
 
 /**
- * Returns a fallback if value is fallback
- * @param {any} value
- * @param {any} whenUndefined
+* @type {Object<string,SpecialAttributeDescriptor>}
 */
-const fallback = (value, whenUndefined) => typeof value != "undefined" ? value : whenUndefined
+const specialAttributes = {
+	value: {
+		get() { return this.value },
+		set(value) {
+			this.setAttribute("value", value)
+			this.value = value
+		},
+		hook(callback) { this.addEventListener("input", callback) }
+	},
+	style: {
+		set(value) { insertStyles(this.style, value) }
+	},
+	dataset: {
+		set(value) {
+			for (const [attribute2, value2] of Object.entries(value)) {
+				this.dataset[attribute2] = processAttribute(value2)
+			}
+		}
+	},
+	shadowRoot: {
+		set(value) {
+			processArgs((this.shadowRoot || this.attachShadow({mode: "open"})), value)
+		}
+	}
+}
 
-/** @typedef {EventTarget & {value: any}} Observable */
+const processAttribute = attribute => {
+	if (typeof attribute == "string" || typeof attribute == "number")
+		return attribute
+	else if (attribute && "join" in attribute)
+		return attribute.join(" ")
+	else
+		return JSON.stringify(attribute)
+}
 
-/** Cancelable event triggered when a reactive element gets replaced with something else */
-export class BeforeReplaceEvent extends Event {
+/** Returns a fallback if value is defined */
+const defined = (value, fallback) => typeof value != "undefined" ? value : fallback
+
+/** Recursively finds the last 'is' attribute in a list nested array of objects
+* @param {Array} args
+*/
+const getCustom = args => args.reduce(
+	(current, argument) => Array.isArray(argument)
+		? defined(getCustom(argument), current)
+		: (argument && typeof argument == "object")
+		? defined(argument.is, current)
+		: current
+	,undefined
+)
+
+/**
+* @typedef Observable
+* @type {EventTarget|object}
+* @property {any} value
+*/
+
+/** Returns whether an object is an observable according to skooma's contract
+* @param {any} object
+* @return {object is Observable}
+*/
+export const isObservable = object => object && object.observable
+
+/** Turns an argument into something that can be inserted as a child into a DOM node
+* @param {any} value
+* @return {Element|Text}
+*/
+const toElement = value => {
+	if (typeof value == "string" || typeof value == "number")
+		return document.createTextNode(value.toString())
+	else if (value instanceof Element)
+		return value
+	else if (isObservable(value))
+		return reactiveElement(value)
+}
+
+class ReplaceEvent extends Event {
 	/** @param {Element|Text} next */
 	constructor(next) {
-		super("beforereplace", { cancelable: true })
+		super("replace", {bubbles: true, cancelable: true})
 		this.next = next
 	}
 }
 
-/** Event triggered when a reactive element was replaced */
-export class AfterReplaceEvent extends Event {
+class ReplacedEvent extends Event {
 	/** @param {Element|Text} next */
 	constructor(next) {
-		super("afterreplace")
+		super("replaced")
 		this.next = next
 	}
 }
 
-/** Event triggered when a new element replaces an old one */
-export class ReplacedEvent extends Event {
-	/** @param {Element|Text} old */
-	constructor(old) {
-		super("replaced", { bubbles: true })
-		this.old = old
+/** @type {WeakMap<Text|Element,Text|Element>} */
+export const newer = new WeakMap()
+
+/**
+* @param {Observable} observable
+* @return {Element|Text}
+*/
+export const reactiveElement = observable => {
+	const element = toElement(observable.value)
+	untilDeathDoThemPart(element, observable)
+	const ref = new WeakRef(element)
+	observable.addEventListener("change", () => {
+		const next = reactiveElement(observable)
+		const element = ref.deref()
+		if (element.dispatchEvent(new ReplaceEvent(next)))
+			element.replaceWith(next)
+		newer.set(this, next)
+		element.dispatchEvent(new ReplacedEvent(next))
+	}, {once: true})
+	return element
+}
+
+/** Set an attribute on an element
+* @param {Element} element
+* @param {string} attribute
+* @param {any} value
+* @param {AbortSignal} [cleanupSignal]
+*/
+const setAttribute = (element, attribute, value, cleanupSignal) => {
+	const special = specialAttributes[attribute]
+	if (isObservable(value))
+		setReactiveAttribute(element, attribute, value)
+	else if (typeof value === "function")
+		element.addEventListener(attribute, value, {signal: cleanupSignal})
+	else if (special?.set)
+		special.set.call(element, value)
+	else if (value === true)
+		{if (!element.hasAttribute(attribute)) element.setAttribute(attribute, '')}
+	else if (value === false)
+		element.removeAttribute(attribute)
+	else {
+		element.setAttribute(attribute, processAttribute(value))
 	}
 }
 
+/** Set up a binding between an attribute and an observable
+* @param {Element} element
+* @param {string} attribute
+* @param {Observable} observable
+*/
+const setReactiveAttribute = (element, attribute, observable) => {
+	const multiAbort = new MultiAbortController()
+
+	observable.addEventListener("change", () => {
+		multiAbort.abort()
+		setAttribute(element, attribute, observable.value, multiAbort.signal)
+	})
+	setAttribute(element, attribute, observable.value, multiAbort.signal)
+
+	const special = specialAttributes[attribute]
+	if (special.hook) {
+		untilDeathDoThemPart(element, observable)
+		special.hook.call(element, () => {
+			const current = special.get.call(element, attribute)
+			if (current != observable.value) observable.value = current
+		})
+	}
+}
+
+/** Processes a list of arguments for an HTML Node
+* @param {Element} element
+* @param {Array} args
+*/
+const processArgs = (element, ...args) => {
+	for (const arg of args) if (arg !== empty) {
+		if (Array.isArray(arg)) {
+			processArgs(element, ...arg)
+		} else {
+			const child = toElement(arg)
+			if (child)
+				element.append(child)
+			else if (arg === undefined || arg == null)
+				console.warn(`An argument of type ${typeof arg} has been ignored`, element)
+			else if (typeof arg == "function" && arg.length == 0)
+				processArgs(element, arg())
+			else if (typeof arg == "function")
+				arg(element)
+			else
+				for (const key in arg)
+					setAttribute(element, key, arg[key])
+		}
+	}
+}
+
+/** Creates a new node
+* @param {String} name
+* @param {Array} args
+* @param {Object} options
+*/
+const node = (name, args, options) => {
+	let element
+	const custom = getCustom(args)
+	const opts = custom && {is: String(custom)}
+
+	if ("nameFilter" in options) name = options.nameFilter(name)
+	if (options.xmlns)
+		element = document.createElementNS(options.xmlns, name, opts)
+	else
+		element = document.createElement(name, opts)
+	processArgs(element, args)
+	return element
+}
+
+const nameSpacedProxy = (options={}) => new Proxy(Window, {
+	/** @param {string} prop */
+	get: (_target, prop, _receiver) => { return (...args) => node(prop, args, options) },
+	has: (_target, _prop) => true,
+})
+
+export const html = nameSpacedProxy({nameFilter: name => name.replace(/([a-z])([A-Z])/g, "$1-$2").toLowerCase()})
+export const svg = nameSpacedProxy({xmlns: "http://www.w3.org/2000/svg"})
+export default html
+
 // Other utility exports
 
 /** Wraps an event handler in a function that calls preventDefault on the event
@@ -79,280 +265,16 @@ export class ReplacedEvent extends Event {
 */
 export const handle = fn => event => { event.preventDefault(); return fn(event) }
 
-
-/** A reference to an element that follows it around through replacements */
-export class Ref {
-	/** @type {WeakMap<Text|Element,Text|Element>} */
-	static #map = new WeakMap()
-
-	/** @type {Element|Text} */
-	#element
-
-	/** @param {Element|Text} element */
-	constructor(element) {
-		this.#element = element
-	}
-
-	/** @return {Element|Text} */
-	deref() {
-		const next = Ref.newer(this.#element)
-		if (next) {
-			this.#element = next
-			return this.deref()
-		} else {
-			return this.#element
-		}
-	}
-
-	/** @param {Element|Text} element */
-	static newer(element) {
-		return this.#map.get(element)
-	}
-
-	/**
-	 * @param {Element|Text} previous
-	 * @param {Element|Text} next
-	 */
-	static replace(previous, next) {
-		if (this.newer(previous))
-			throw "Element has already been replaced with newer one"
-		this.#map.set(previous, next)
-	}
-}
-
-/** Main class doing all the rendering */
-export class Renderer {
-	static proxy() {
-		return new Proxy(new this(), {
-			/** @param {string} prop */
-			get: (renderer, prop) => /** @param {any[]} args */ (...args) => renderer.node(prop, args),
-			has: (renderer, prop) => renderer.nodeSupported(prop),
-		})
-	}
-
-	/** @param {string} name */
-	node(name, ...args) {
-		throw "Attempting to use an abstract Renderer"
-	}
-
-	/** @param {string|symbol} name */
-	nodeSupported(name) {
-		if (typeof(name) != "string") return false
-		return true
-	}
-
-	/** Turns an attribute value into a string */
-	/** @param {any} value */
-	static serialiseAttributeValue(value) {
-		if (typeof value == "string" || typeof value == "number")
-			return value
-		else if (value && "join" in value)
-			return value.join(" ")
-		else if (Object.getPrototypeOf(value) == Object.prototype)
-			return JSON.stringify(value)
-		else
-			return value.toString()
-	}
-}
-
-export class DomRenderer extends Renderer {
-	/** @type {Object<string,SpecialAttributeDescriptor>} */
-	static specialAttributes = Object.freeze({})
-
-	/** Processes a list of arguments for an HTML Node
-	 * @param {Element|ShadowRoot} element
-	 * @param {Array} args
-	 */
-	static apply(element, ...args) {
-		for (const arg of args) if (arg !== empty) {
-			if (Array.isArray(arg)) {
-				this.apply(element, ...arg)
-			} else {
-				const child = this.toElement(arg)
-				if (child)
-					element.append(child)
-				else if (typeof arg == "function")
-					this.apply(element, arg(element) || empty)
-				else if (arg && typeof(arg)=="object")
-					for (const key in arg)
-						if (element instanceof Element)
-							this.setAttribute(element, key, arg[key])
-						else
-							throw `Attempting to set attributes on a non-element (${element.constructor.name})`
-				else
-					console.warn(`An argument of type ${typeof arg} has been ignored`, element)
-			}
-		}
-	}
-
-	/** Creates a new node
-	 * @param {String} name
-	 * @param {Array} args
-	 */
-	node(name, args) {
-		const element = this.createElement(name)
-		this.constructor.apply(element, args)
-		return element
-	}
-
-	/**
-	 * @protected
-	 * @param {String} name
-	 * @param {Object} options
-	 * @return {Node}
-	 */
-	createElement(name, options={}) {
-		return document.createElement(name, options)
-	}
-
-	/** Turns an argument into something that can be inserted as a child into a DOM node
-	 * @protected
-	 * @param {any} value
-	 * @return {Element|Text}
-	 */
-	static toElement(value) {
-		if (typeof value == "string" || typeof value == "number")
-			return document.createTextNode(value.toString())
-		else if (value instanceof Element)
-			return value
-		else if (this.isObservable(value))
-			return this.toReactiveElement(value)
-	}
-
-	/**
-	 * @protected
-	 * @param {Observable} observable
-	 * @return {Element|Text}
-	 */
-	static toReactiveElement(observable) {
-		const element = this.toElement(observable.value)
-		untilDeathDoThemPart(element, observable)
-		let ref = new WeakRef(element)
-
-		const handleChange = () => {
-			const element = ref.deref()
-
-			if (!element) return
-
-			const next = this.toElement(observable.value)
-			if (element?.dispatchEvent(new BeforeReplaceEvent(next))) {
-				element.replaceWith(next)
-				Ref.replace(element, next)
-				next.dispatchEvent(new ReplacedEvent(element))
-				element.dispatchEvent(new AfterReplaceEvent(next))
-				ref = new WeakRef(next)
-			}
-			observable.addEventListener("change", handleChange, {once: true})
-		}
-		observable.addEventListener("change", handleChange, {once: true})
-
-		return element
-	}
-
-	/** Set an attribute on an element
-	 * @protected
-	 * @param {Element} element
-	 * @param {string} attribute
-	 * @param {any} value
-	 * @param {AbortSignal} [cleanupSignal]
-	 */
-	static setAttribute(element, attribute, value, cleanupSignal) {
-		const special = this.getSpecialAttribute(element, attribute)
-
-		if (this.isObservable(value))
-			this.setReactiveAttribute(element, attribute, value)
-		else if (typeof value === "function")
-			element.addEventListener(attribute, value, { signal: cleanupSignal })
-		else if (special?.set)
-			special.set(element, value)
-		else if (value === true)
-			{ if (!element.hasAttribute(attribute)) element.setAttribute(attribute, '') }
-		else if (value === false)
-			element.removeAttribute(attribute)
-		else {
-			element.setAttribute(attribute, this.serialiseAttributeValue(value))
-		}
-	}
-
-	/** Set up a binding between an attribute and an observable
-	 * @protected
-	 * @param {Element} element
-	 * @param {string} attribute
-	 * @param {Observable} observable
-	 */
-	static setReactiveAttribute(element, attribute, observable) {
-		const multiAbort = new MultiAbortController()
-
-		observable.addEventListener("change", () => {
-			multiAbort.abort()
-			this.setAttribute(element, attribute, observable.value, multiAbort.signal)
-		})
-		this.setAttribute(element, attribute, observable.value, multiAbort.signal)
-
-		const special = this.getSpecialAttribute(element, attribute)
-
-		if (special?.subscribe) {
-			untilDeathDoThemPart(element, observable)
-			special.subscribe(element, value => {
-				if (value != observable.value) observable.value = value
-			})
-		}
-	}
-
-	/**
-	 * @param {CSSStyleDeclaration} style The style property of a node
-	 * @param {object} rules A map of snake case property names to css values
-	 */
-	static insertStyles(style, rules) {
-		for (const [key, value] of Object.entries(rules))
-			if (typeof value == "undefined")
-				style.removeProperty(snakeToCSS(key))
-			else
-				style.setProperty(snakeToCSS(key), value.toString())
-	}
-
-	/** Returns whether an object is an observable according to skooma's contract
-	 * @param {any} object
-	 * @return {object is Observable}
-	 */
-	static isObservable(object) {
-		return object && object.observable
-	}
-
 /** Wraps a list of elements in a document fragment
 * @param {Array<Element|String>} elements
 */
-	static documentFragment(...elements) {
+export const fragment = (...elements) => {
 	const fragment = new DocumentFragment()
 	for (const element of elements)
-			fragment.append(this.toElement(element))
+		fragment.append(toElement(element))
 	return fragment
 }
 
-	/**
-	 * @protected
-	 * @param {Element} element
-	 * @param {String} attribute
-	 */
-	static getSpecialAttribute(element, attribute) {
-		const special = this.specialAttributes[attribute]
-		if (special?.filter == undefined)
-			return special
-		if (special.filter(element))
-			return special
-		return undefined
-	}
-
-	/**
-	 * @param {String|Array<String>} data
-	 * @param {Array<String|Element>} items
-	 */
-	static createTextOrFragment(data = "", ...items) {
-		return Array.isArray(data)
-			? this.textFromTemplate(data, items)
-			: document.createTextNode(data)
-	}
-
 /** Turns a template literal into document fragment.
 * Strings are returned as text nodes.
 * Elements are inserted in between.
@@ -360,116 +282,21 @@ export class DomRenderer extends Renderer {
 * @param {Array<any>} items
 * @return {DocumentFragment}
 */
-	static textFromTemplate(literals, items) {
+const textFromTemplate = (literals, items) => {
 	const fragment = new DocumentFragment()
 	for (const key in items) {
 		fragment.append(document.createTextNode(literals[key]))
-			fragment.append(this.toElement(items[key]))
+		fragment.append(toElement(items[key]))
 	}
 	fragment.append(document.createTextNode(literals[literals.length-1]))
 	return fragment
 }
-}
 
-/** Renderer for normal HTML nodes targetting a browser's DOM */
-export class DomHtmlRenderer extends DomRenderer {
 /**
-	 * @param {String} name
-	 * @param {Object} options
-	 * @return {Node}
+* @param {String|Array<String>} data
+* @param {Array<String|Element>} items
 */
-	createElement(name, options) {
-		return document.createElement(name.replace(/([a-z])([A-Z])/g, "$1-$2"), options)
-	}
-
-	/** Creates a new node and make it a custom element if necessary
-	 * @param {String} name
-	 * @param {Array} args
-	 */
-	node(name, args) {
-		const custom = this.getCustom(args)
-		const opts = custom && { is: String(custom) }
-
-		const element = this.createElement(name, opts)
-		this.constructor.apply(element, args)
-		return element
-	}
-
-	/** Recursively finds the last 'is' attribute in a list nested array of objects
-	 * @param {Array} args
-	 */
-	getCustom(args) {
-		return args.reduce(
-			(current, argument) => Array.isArray(argument)
-				? fallback(this.getCustom(argument), current)
-				: (argument && typeof argument == "object")
-					? fallback(argument.is, current)
-					: current
-			, undefined
-		)
-	}
-
-	/** @type {Object<string,SpecialAttributeDescriptor>} */
-	static specialAttributes = {
-		value: {
-			/** @param {HTMLInputElement} element */
-			get(element) { return element.value },
-			/** @param {HTMLInputElement} element */
-			set(element, value) {
-				element.setAttribute("value", value)
-				element.value = value
-			},
-			/** @param {HTMLInputElement} element */
-			subscribe(element, callback) {
-				element.addEventListener("input", () => {
-					callback(this.get(element))
-				})
-			},
-			/** @param {HTMLElement} element */
-			filter(element) {
-				return element.nodeName.toLowerCase() == "input"
-			}
-		},
-		style: {
-			/** @param {HTMLElement} element */
-			set(element, value) { DomRenderer.insertStyles(element.style, value) }
-		},
-		dataset: {
-			/** @param {HTMLElement} element */
-			set(element, value) {
-				for (const [attribute2, value2] of Object.entries(value)) {
-					element.dataset[attribute2] = DomRenderer.serialiseAttributeValue(value2)
-				}
-			}
-		},
-		shadowRoot: {
-			/** @param {HTMLElement} element */
-			set(element, value) {
-				DomRenderer.apply(
-					(element.shadowRoot || element.attachShadow({ mode: "open" })),
-					value
-				)
-			}
-		}
-	}
-}
-
-/** Renderer for normal SVG nodes targetting a browser's DOM */
-export class DomSvgRenderer extends DomRenderer {
-	/**
-	 * @param {String} name
-	 * @param {Object} options
-	 * @return {Node}
-	 */
-	createElement(name, options) {
-		return document.createElementNS("http://www.w3.org/2000/svg", name, options)
-	}
-}
-
-export const html = DomHtmlRenderer.proxy()
-export const svg = DomSvgRenderer.proxy()
-
-export const fragment = DomRenderer.documentFragment.bind(DomRenderer)
-export const text = DomRenderer.createTextOrFragment.bind(DomRenderer)
-
-export default html
+export const text = (data="", ...items) =>
+	Array.isArray(data)
+		? textFromTemplate(data, items)
+		: document.createTextNode(data)