Adjust signal again

engine/lib/Signal.ts

@@ -4,22 +4,17 @@ let current: Current = null;
 
 export function createSignal<T>(value: T): [() => T, (value: T) => void] {
 	let innerValue = value;
-	const observers: Array<Current> = [];
-	const indices = new Map<Current, number>();
+	const observers = new Set<() => void>();
 
 	const getter = () => {
-		if (current !== null && !indices.has(current)) {
-			observers.push(current);
-			indices.set(current, observers.length);
-		}
-
+		current !== null && observers.add(current);
 		return innerValue;
 	};
 
 	const setter = (value: T) => {
 		innerValue = value;
-		for (let i = 0; i < observers.length; i++) {
-			observers[i]!();
+		for (const observer of observers) {
+			observer();
 		}
 	};