observable.js

@@ -21,16 +21,16 @@ const target = Symbol("Proxy Target")
  */
 
 /** Event fired for every change before the internal state has been updated that can be canceled. */
-export class ChangeEvent extends Event {
+export class SynchronousChangeEvent extends Event {
 	/** @param {Change} change */
 	constructor(change) {
-		super('change', {cancelable: true})
+		super('synchronous', {cancelable: true})
 		this.change = Object.freeze(change)
 	}
 }
 
 /** Event fired for one or more changed values after the internal state has been updated. */
-export class ChangedEvent extends Event {
+export class MultiChangeEvent extends Event {
 	/** @type {any} */
 	#final
 	/** @type {any} */
@@ -71,6 +71,14 @@ export class ChangedEvent extends Event {
 	}
 }
 
+export class ValueChangeEvent extends MultiChangeEvent {
+	get value() {
+		return this.final.value
+	}
+}
+
+/* Observable Classes */
+
 export class Observable extends EventTarget {
 	#synchronous
 	/** @type Change[]> */
@@ -95,11 +103,6 @@ export class Observable extends EventTarget {
 		})
 	}
 
-	/** @param {Change[]} changes */
-	emit(...changes) {
-		this.dispatchEvent(new ChangedEvent(...changes))
-	}
-
 	/**
 	 * @param {string} prop
 	 */
@@ -133,7 +136,7 @@ export class Observable extends EventTarget {
 	 */
 	enqueue(property, from, to, mutation=false) {
 		const change = {property, from, to, mutation}
-		if (!this.dispatchEvent(new ChangeEvent(change))) return false
+		if (!this.dispatchEvent(new SynchronousChangeEvent(change))) return false
 		if (!this.synchronous) {
 			if (!this.#queue) {
 				this.#queue = []
@@ -149,13 +152,17 @@ export class Observable extends EventTarget {
 		return true
 	}
 
+	/** @param {any[]} _args */
+	emit(..._args) {
+		throw new TypeError(`${this.constructor.name} did not define an 'emit' method`)
+	}
+
 	get signal() { return this.#abortController.signal }
 	get synchronous() { return this.#synchronous }
-
-	get changesQueued() { return Boolean(this.#queue) }
 }
 
 export class ObservableObject extends Observable {
+
 	/**
 	 * @param {Object} target
 	 * @param {Object} options
@@ -205,10 +212,15 @@ export class ObservableObject extends Observable {
 		return proxy
 	}
 
+	/** @param {Change[]} changes */
+	emit(...changes) {
+		this.dispatchEvent(new MultiChangeEvent(...changes))
+	}
+
 	/** @type Map<Observable, Map<String, Function>> */
 	#nested = new Map()
 
-	/** Adopts an observable to be notified of its changes
+	/** Adopts an obsercable to be notified of its changes
 	 * @param {string} prop
 	 * @param {Observable} observable
 	 */
@@ -260,9 +272,20 @@ export class ObservableValue extends Observable {
 		}
 	}
 
+	/**
+	 * @param {string} prop
+	 * @param {function(any):void} callback
+	 */
+	subscribe(prop, callback) {
+		// @ts-ignore
+		if (typeof(prop) == "function") [prop, callback] = ["value", prop]
+
+		this.constructor.prototype.subscribe.call(this, prop, callback)
+	}
+
 	/** @param {Change[]} changes */
 	emit(...changes) {
-		this.dispatchEvent(new ChangedEvent(...changes))
+		this.dispatchEvent(new ValueChangeEvent(...changes))
 	}
 }
 
@@ -302,7 +325,7 @@ class ProxiedObservableValue extends ObservableValue {
 
 const attributeObserver = new MutationObserver(mutations => {
 	for (const {type, target, attributeName: name} of mutations) {
-		if (type == "attributes" && target instanceof HTMLElement) {
+		if (type == "attributes") {
 			const next = target.getAttribute(name)
 			const camelName = kebabToCamel(name)
 			if (String(target.state.values[camelName]) !== next)
@@ -317,21 +340,17 @@ export const component = (name, generator, methods) => {
 		generator = name
 		name = camelToKebab(generator.name)
 	}
-	component[kebabToCamel(name)] = class extends HTMLElement{
-		/** @type {ObservableObject} */
-		state
-
+	const Element = class extends HTMLElement{
 		constructor() {
 			super()
 			const target = Object.fromEntries([...this.attributes].map(attribute => [kebabToCamel(attribute.name), attribute.value]))
 			this.state = new ObservableObject(target)
-			this.state.addEventListener("changed", event => {
-				if (event instanceof ChangedEvent)
-					for (const {property, to: value} of event.changes) {
-						const kebabName = camelToKebab(property)
-						if (this.getAttribute(kebabName) !== String(value))
-							this.setAttribute(kebabName, value)
-					}
+			this.state.addEventListener("change", event => {
+				for (const {property, to: value} of event.changes) {
+					const kebabName = camelToKebab(property)
+					if (this.getAttribute(kebabName) !== String(value))
+						this.setAttribute(kebabName, value)
+				}
 			})
 			attributeObserver.observe(this, {attributes: true})
 			const content = generator.call(this, this.state)
@@ -345,26 +364,21 @@ export const component = (name, generator, methods) => {
 	return Element;
 }
 
-class Composition extends ObservableValue {
+class ObservableComposition extends ObservableValue {
 	#func
 	#states
 
-	/**
-	 * @param {(...values: any[]) => any} func
-	 * @param {Object} options
-	 * @param {Observable[]} states
-	 */
-	constructor(func, options, ...obesrvables) {
+	constructor(func, options, ...states) {
 		super(options)
 
 		this.#func = func
-		this.#states = obesrvables
+		this.#states = states
 
 		const abortController = new AbortController()
 		abortRegistry.register(this, abortController)
 		const ref = new WeakRef(this)
 
-		obesrvables.forEach(state => {
+		states.forEach(state => {
 			state.addEventListener("change", () => {
 				ref.deref()?.scheduleUpdate()
 			}, {signal: abortController.signal})
@@ -373,7 +387,7 @@ class Composition extends ObservableValue {
 		this.update()
 	}
 
-	#microtaskQueued = false
+	#microtaskQueued
 	scheduleUpdate() {
 		if (this.synchronous) {
 			this.update()
@@ -396,12 +410,106 @@ class Composition extends ObservableValue {
 	}
 }
 
-/**
- * @param {Function} func
- */
-export const compose = func =>
+export const compose = func => (...states) => new ObservableComposition(func, {}, ...states)
+
+class MutationEvent extends Event {
+	constructor() {
+		super("mutation", {bubbles: true})
+	}
+}
+
+const mutationObserver = new MutationObserver(mutations => {
+	for (const mutation of mutations) {
+		mutation.target.dispatchEvent(new MutationEvent())
+	}
+})
+
+export class ObservableElement extends Observable {
+	#getValue
+	#equal
+
+	#value
+	#changedValue = false
+
 	/**
-	 * @param {Observable[]} observables
+	 * @param {HTMLElement} target
 	 */
-	(...observables) =>
-		new Composition(func, {}, ...observables)
+	constructor(target, {get=undefined, equal=undefined, ...options}={}) {
+		// @ts-ignore
+		super(options)
+		Object.defineProperty(this, "target", {value: target, configurable: false, writable: false})
+
+		this.#getValue = get ?? (target => target.value)
+		this.#equal = equal ?? ((a, b) => a===b)
+
+		this.#value = this.#getValue(target)
+
+		const controller = new AbortController()
+		target.addEventListener("mutation", event => { this.update(event) }, {signal: controller.signal})
+
+		abortRegistry.register(this, controller)
+		mutationObserver.observe(target, {
+			attributes: true,
+			childList: true,
+			characterData: true,
+			subtree: true,
+		})
+	}
+
+	get value() { return this.#value }
+
+	update() {
+		const current = this.#getValue(this.target)
+
+		if (this.#equal(this.#value, current)) return
+
+		this.#value = current
+
+		if (this.synchronous) {
+			this.dispatchEvent(new ValueChangeEvent(["value", current]))
+		} else {
+			if (!this.#changedValue) {
+				queueMicrotask(() => {
+					this.#changedValue = false
+					this.dispatchEvent(new ValueChangeEvent(["value", this.#changedValue]))
+				})
+				this.#changedValue = current
+			}
+		}
+	}
+}
+
+export class MapStorage extends Storage {
+	#map = new Map()
+	/**
+	 * @param {number} index
+	 * @return {string}
+	 */
+	key(index) {
+		return [...this.#map.keys()][index]
+	}
+	/**
+	 * @param {string} keyName
+	 * @return {any}
+	 */
+	getItem(keyName) {
+		if (this.#map.has(keyName))
+			return this.#map.get(keyName)
+		else
+			return null
+	}
+	/**
+	 * @param {string} keyName
+	 * @param {any} keyValue
+	 */
+	setItem(keyName, keyValue) {
+		this.#map.set(keyName, String(keyValue))
+	}
+	/** @param {string} keyName */
+	removeItem(keyName) {
+		this.#map.delete(keyName)
+	}
+	clear() {
+		this.#map.clear()
+	}
+}

readme.md

@@ -1,10 +1,44 @@
 # Nyooom
 
 ```js
-import {html} from "nyooom/render"
-import {ObservableValue} from "nyooom/observable"
+import {html} from "nyooom/render.js"
 
-const text = new ObservableValue("Nyooom is cool")
+document.body.append(
+	html.p(
+		"This is a paragraph with some text ",
+		html.b("and some bold text "),
+		html.img({
+			alt: "And an image",
+			href: "http://picsum.photos/200/200"
+		})
+	)
+)
+```
+
+## Goals
+
+1. `nyooom/render` should stay small enough to use it as just a helper library
+   to generate some dom nodes in any sort of web environment.
+1. `nyooom/observable` should likewise function as a standalone reactive state
+   management library to be used with or without a framework
+1. A developer who doesn't use nyooom should be able to read any code using it
+   and piece together what it does based on structure and function names
+1. Nyooom should be easy to gradually introduce into an application that uses
+   a different framework or no framework at all
+1. Nyooom should make it easy to gradually replace it with a different solution
+   should it prove unfit for a project it is being used in
+1. The library should be hackable so that developers can tweak it for different
+   environments like SSR or frameworks
+
+## Warning
+
+**This branch is in the process of being aggressively refactored and improved.
+This readme file may not reflect the latest state of the interface.**
+
+## Overview
+
+```js
+const text = new State({value: "Nyooom is cool"})
 setTimeout(() => {text.value = "Nyooom is awesome!"}, 1e5)
 
 document.body.append(html.div(
@@ -14,21 +48,6 @@ document.body.append(html.div(
 ))
 ```
 
-## Goals
-
-> Arrakis teaches the attitude of the knife - chopping off what's incomplete and
-> saying: "Now, it's complete because it's ended here."
-> 
-> — Frank Herbert, Dune
-
-Nyooom aims to offer as much convenienve as possible within the following
-constraints:
-
-1. Small, independent modules that can also work on their own
-1. Code should be easy to figure out by someone who doesn't actiely use nyooom
-1. Easy to gradually introduce and remove rather than forcing big re-writes
-1. Flexible, hackable and easy to audit
-
 ## Importmaps
 
 The included file `importmaps.html` can be used as a starting point for

render.js

@@ -220,9 +220,9 @@ export class DomRenderer extends Renderer {
 				element.dispatchEvent(new AfterReplaceEvent(next))
 				ref = new WeakRef(next)
 			}
-			observable.addEventListener("changed", handleChange, {once: true})
+			observable.addEventListener("change", handleChange, {once: true})
 		}
-		observable.addEventListener("changed", handleChange, {once: true})
+		observable.addEventListener("change", handleChange, {once: true})
 
 		return element
 	}
@@ -261,7 +261,7 @@ export class DomRenderer extends Renderer {
 	static setReactiveAttribute(element, attribute, observable) {
 		const multiAbort = new MultiAbortController()
 
-		observable.addEventListener("changed", () => {
+		observable.addEventListener("change", () => {
 			multiAbort.abort()
 			if (element.dispatchEvent(new AttributeEvent(attribute, element.getAttribute(attribute), observable.value)))
 				this.setAttribute(element, attribute, observable.value, multiAbort.signal)