From 77cb9cf6264f37a294f4c17c4113b32bb53a48bf Mon Sep 17 00:00:00 2001
From: Jan Andrle <andrle.jan@centrum.cz>
Date: Fri, 25 Aug 2023 20:45:02 +0200
Subject: [PATCH] :sparkles: Add signal listener, reactive and wrap object
 functions

---
 src/events.js  |  4 +--
 src/signals.js | 93 +++++++++++++++++++++++++++++++++++++++-----------
 test/index.js  |  6 ++--
 3 files changed, 79 insertions(+), 24 deletions(-)

diff --git a/src/events.js b/src/events.js
index 966d4fd..3511114 100644
--- a/src/events.js
+++ b/src/events.js
@@ -1,6 +1,6 @@
-import { isSignal } from './signals.js';
+import { isSignal, addSignalListener } from './signals.js';
 export function on(event, listener, options){
-	if(isSignal(event)) return event.listeners.add(listener);
+	if(isSignal(event)) return addSignalListener(event, listener);
 	return element=> element.addEventListener(event, listener, options);
 }
 export function dispatch(event, detail){
diff --git a/src/signals.js b/src/signals.js
index 1420926..6d17d44 100644
--- a/src/signals.js
+++ b/src/signals.js
@@ -3,15 +3,41 @@ export function isSignal(candidate){
 	try{ return Reflect.has(candidate, mark); }
 	catch(e){ return false; }
 }
-export function S(signal){
-	if(typeof signal!=="function")
-		return create(signal);
-	if(isSignal(signal)) return signal;
+export function addSignalListener(signal, listener){
+	return signal[mark].listeners.add(listener);
+}
+export function S(value){
+	if(typeof value!=="function")
+		return create(value);
+	if(isSignal(value)) return value;
 	
 	const out= create();
-	watch(()=> out(signal()));
+	watch(()=> out(value()));
 	return out;
 }
+export function reactive(data){
+	if(isSignal(data))
+		return data;
+	if(typeof data!=="object" || data===null)
+		return create(data);
+	
+	let type;
+	if(Array.isArray(data)){
+		type= "array";
+		data= data.map(v=> reactive(v));
+	} else if(data.toString()!=="[object Object]"){
+		return create(data);
+	} else {
+		type= "object";
+		data= Object.fromEntries(
+			Object.entries(data)
+			.map(([ key, value ])=> [ key, reactive(value) ])
+		);
+	}
+	const signal= (...value)=>
+		value.length ? write(signal, reactive(value[0])) : read(signal[mark]);
+	return createWrapObject(type, toSignal(signal, data));
+}
 const stack= [];
 export function watch(context){
 	stack.push(context);
@@ -24,28 +50,57 @@ function currentContext(){
 }
 function create(value){
 	if(isSignal(value)) return value;
-	
-	if(typeof value==="object" && value!==null)
-		//TODO Array?
-		return Object.fromEntries(
-			Object.entries(value)
-			.map(([ key, value ])=> [ key, create(value) ])
-		);
-	const signal= (...value)=>
-		value.length ? write(signal, value[0]) : read(signal);
-	Object.assign(signal, {
-		[mark]: true,
+	const signal=  (...value)=>
+		value.length ? write(signal, value[0]) : read(signal[mark]);
+	return toSignal(signal, value);
+}
+function toSignal(signal, value){
+	signal[mark]= {
 		value,
 		listeners: new Set()
-	});
+	};
 	return signal;
 }
+function createWrapObject(type, signal){
+	return new Proxy(signal, {
+		set(_, p, newValue){
+			const s= signal[mark];
+			if(p in s.value){
+				const v= s.value[p];
+				if(isSignal(v)) return v(newValue);
+				return (s.value[p]= newValue);
+			}
+			const v= reactive(newValue);
+			s.value[p]= v;
+			s.listeners.forEach(fn=> fn(s.value));
+			return v;
+		},
+		deleteProperty(_, p){
+			const s= signal[mark];
+			Reflect.deleteProperty(s.value, p);
+			s.listeners.forEach(fn=> fn(s.value));
+		},
+		get(_, p){
+			if(mark===p) return signal[mark];
+			if("array"!==type || !(p in Array.prototype) || p==="length")
+				return Reflect.get(signal[mark].value, p);
+			return (...a)=> {
+				const s= signal[mark];
+				const result= Array.prototype[p].call(s.value, ...a);
+				//TODO optimize!
+				s.value.forEach((v, i)=> Reflect.set(s.value, i, reactive(v)));
+				s.listeners.forEach(fn=> fn(s.value));
+				return result;
+			};
+		}
+	});
+}
 function read({ value, listeners }){
 	const context= currentContext();
 	if(context) listeners.add(context);
 	return value;
 }
 function write(signal, value){
-	signal.value= value;
-	signal.listeners.forEach(fn=> fn(value))
+	signal[mark].value= value;
+	signal[mark].listeners.forEach(fn=> fn(value))
 }
diff --git a/test/index.js b/test/index.js
index 9e26d95..7c83861 100644
--- a/test/index.js
+++ b/test/index.js
@@ -1,5 +1,5 @@
-import { S, watch, el, namespace, assign, on, dispatch } from "../index.js";
-Object.assign(globalThis, { S, watch, el, namespace, assign, on, dispatch });
+import { S, reactive, watch, el, namespace, assign, on, dispatch } from "../index.js";
+Object.assign(globalThis, { S, reactive, watch, el, namespace, assign, on, dispatch });
 
 const { style, css }= createStyle();
 globalThis.test= console.log;
@@ -21,7 +21,7 @@ function component({ name= "World", surname= "" }= {}){
 			margin-inline-start: .5em;
 		}
 	`;
-	const store= S({ name, surname });
+	const store= reactive({ name, surname });
 	const full_name= S(()=> store.name()+" "+store.surname());
 	on(full_name, console.log);