💥 Signals are now optional + reactive element

- `registerReactivity` can be used to register custom behavior
- Signals are automatically registered when `signals.js` is imported;
- `el("<>", signal, map)`

index.js

@@ -4,4 +4,3 @@
 });
 export * from "./src/dom.js";
 export * from "./src/events.js";
-export * from "./src/signals.js";

src/dom.js

@@ -1,3 +1,5 @@
+import { signals } from "./signals-common.js";
+
 let namespace_curr= "html";
 export function namespace(namespace){
 	namespace_curr= namespace==="svg" ? "http://www.w3.org/2000/svg" : namespace;
@@ -5,15 +7,17 @@ export function namespace(namespace){
 		append(el){ namespace_curr= "html"; return el; }
 	};
 }
-import { typeOf } from './helpers.js';
-import { isSignal, valueOfSignal } from './signals-common.js';
 export function createElement(tag, attributes, ...connect){
-	if(typeOf(attributes)!=="[object Object]" || ( isSignal(attributes) && typeOf(valueOfSignal(attributes))!=="[object Object]" ))
-		attributes= { textContent: attributes };
 	let el;
+	if("<>"===tag){
+		if(signals.isReactiveAtrribute(attributes))
+			return signals.reactiveElement(attributes, ...connect);
+		el= document.createDocumentFragment();
+	}
+	if(signals.isTextContent(attributes))
+		attributes= { textContent: attributes };
 	switch(true){
 		case typeof tag==="function": el= tag(attributes || undefined); break;
-		case tag==="<>":              el= document.createDocumentFragment(); break;
 		case tag==="#text":           el= assign(document.createTextNode(""), attributes); break;
 		case namespace_curr!=="html": el= assign(document.createElementNS(namespace_curr, tag), attributes); break;
 		default:                      el= assign(document.createElement(tag), attributes);
@@ -23,17 +27,14 @@ export function createElement(tag, attributes, ...connect){
 }
 export { createElement as el };
 
-import { addSignalListener } from './signals-common.js';
 export function assign(element, ...attributes){
 	if(!attributes.length) return element;
 	const is_svg= element instanceof SVGElement;
 	const setRemoveAttr= (is_svg ? setRemoveNS : setRemove).bind(null, element, "Attribute");
 	
 	Object.entries(Object.assign({}, ...attributes)).forEach(function assignNth([ key, attr ]){
-		if(isSignal(attr)){ //TODO: unmounted
-			addSignalListener(attr, attr=> assignNth([ key, attr ]));
-			attr= attr();
-		}
+		if(signals.isReactiveAtrribute(attr, key))
+			attr= signals.process(key, attr, assignNth);
 		if(key[0]==="=") return setRemoveAttr(key.slice(1), attr);
 		if(key[0]===".") return setDelete(element, key.slice(1), attr);
 		if(typeof attr === "object"){

src/events.js

@@ -1,11 +1,13 @@
-import { isSignal, addSignalListener, removeSignalListener } from './signals-common.js';
+import { signals } from './signals-common.js';
+export { registerReactivity } from './signals-common.js';
+
 export function on(event, listener, options){
-	if(!isSignal(event))
+	if(!signals.isReactiveAtrribute(event))
 		return element=> element.addEventListener(event, listener, options);
 	//TODO cleanup when signal removed (also TODO)
 	if(options && options.signal)
-		options.signal.addEventListener("abort", ()=> removeSignalListener(event, listener));
-	return addSignalListener(event, listener);
+		options.signal.addEventListener("abort", ()=> signals.off(event, listener));
+	return signals.on(event, listener);
 }
 export function off(){//TODO is needed?
 	const abort= new AbortController();

src/signals-common.js

@@ -1,23 +1,12 @@
-export const mark= Symbol.for("signal");
-
-export function isSignal(candidate){
-	try{ return Reflect.has(candidate, mark); }
-	catch(e){ return false; }
-}
-export function valueOfSignal(signal){
-	return signal[mark].value;
-}
-export function toSignal(signal, value){
-	signal[mark]= {
-		value,
-		listeners: new Set()
-	};
-	return signal;
-}
-
-export function addSignalListener(signal, listener){
-	return signal[mark].listeners.add(listener);
-}
-export function removeSignalListener(signal, listener){
-	return signal[mark].listeners.delete(listener);
+import { typeOf } from './helpers.js';
+export const signals= {
+	isReactiveAtrribute(attr, key){ return false; },
+	isTextContent(attributes){ return typeOf(attributes)!=="[object Object]"; },
+	process(key, attr, assignNth){ return false; },
+	on(signal, listener){ return false; },
+	off(signal, listener){ return false; },
+	reactiveElement(attributes, ...connect){ return document.createDocumentFragment(); }
+};
+export function registerReactivity(def){
+	return Object.assign(signals, def);
 }

src/signals.js

@@ -1,5 +1,41 @@
-import { mark, isSignal, toSignal, addSignalListener } from "./signals-common.js";
-export { isSignal, addSignalListener };
+export const mark= Symbol.for("signal");
+
+export function isSignal(candidate){
+	try{ return Reflect.has(candidate, mark); }
+	catch(e){ return false; }
+}
+import { typeOf } from './helpers.js';
+import { registerReactivity } from "./signals-common.js";
+registerReactivity({
+	isReactiveAtrribute(attr, key){ return isSignal(attr); },
+	isTextContent(attributes){
+		//TODO FIX el(…, S.reactive(…))
+		return typeOf(attributes)!=="[object Object]" || ( isSignal(attributes) && typeOf(valueOfSignal(attributes))!=="[object Object]" );
+	},
+	process(key, attr, assignNth){ //TODO: unmounted
+		addSignalListener(attr, attr=> assignNth([ key, attr ]));
+		return attr();
+	},
+	on: addSignalListener,
+	off: removeSignalListener,
+	reactiveElement(signal, map){
+		const mark= document.createComment("reactive");
+		const out= document.createDocumentFragment();
+		out.append(mark);
+		let cache;
+		const toEls= v=> {
+			let els= map(v);
+			if(!Array.isArray(els))
+				els= [ els ];
+			if(cache) cache.forEach(el=> el.remove());
+			cache= els;
+			mark.before(...els);
+		};
+		addSignalListener(signal, toEls);
+		toEls(signal());
+		return out;
+	}
+});
 
 export function S(value){
 	if(typeof value!=="function")
@@ -34,6 +70,14 @@ function reactive(data){
 		value.length ? write(signal, reactive(value[0])) : read(signal[mark]);
 	return createWrapObject(type, toSignal(signal, data));
 };
+function toSignal(signal, value){
+	signal[mark]= {
+		value,
+		listeners: new Set()
+	};
+	return signal;
+}
+
 const stack= [];
 export function watch(context){
 	stack.push(function contextReWatch(){
@@ -98,3 +142,12 @@ function write(signal, value){
 	signal[mark].listeners.forEach(fn=> fn(value))
 	return value;
 }
+function valueOfSignal(signal){
+	return signal[mark].value;
+}
+export function addSignalListener(signal, listener){
+	return signal[mark].listeners.add(listener);
+}
+export function removeSignalListener(signal, listener){
+	return signal[mark].listeners.delete(listener);
+}

test/index.js

@@ -1,4 +1,5 @@
-import { S, el, on, off } from "../index.js";
+import { el, on, off } from "../index.js";
+import { S } from "../src/signals.js";
 //import { empty, namespace, on, dispatch } from "../index.js";
 Object.assign(globalThis, { S, el, on, off });
 
@@ -39,8 +40,7 @@ function todosComponent({ todos= [] }= {}){
 	return el("div", { className }).append(
 		el("div").append(
 			el("h1", "Todos:"),
-			elR(todos,
-				ts=> !ts.length
+			el("<>", todos, ts=> !ts.length
 				? el("p", "No todos yet")
 				: ts.map((t, i)=> el(todoComponent, { textContent: t, value: i, className }, onremove)))
 		),
@@ -64,22 +64,6 @@ function todoComponent({ textContent, className, value }){
 		el("button", { type: "button", value, textContent: "-" })
 	);
 }
-function elR(signal, map){
-	const mark= document.createComment("reactive");
-	const out= el("<>").append(mark);
-	let cache;
-	const toEls= v=> {
-		let els= map(v);
-		if(!Array.isArray(els))
-			els= [ els ];
-		if(cache) cache.forEach(el=> el.remove());
-		cache= els;
-		mark.before(...els);
-	};
-	on(signal, toEls);
-	toEls(signal());
-	return out;
-}
 function createStyle(){
 	const element= el("style");
 	const store= new WeakSet();