Merge pull request #69 from Battosuai/fix/memory-leak-mixin-tracking

fix: weakmap in mixing tracking

src/mixin-tracking.ts

@@ -2,17 +2,18 @@ import { protoChain } from './util';
 import { Class } from './types';
 
 // Keeps track of constituent classes for every mixin class created by ts-mixer.
-const mixins = new Map<any, Function[]>();
+const mixins = new WeakMap<any, Function[]>();
 
-export const getMixinsForClass = (clazz: Class) =>
-	mixins.get(clazz);
+export const getMixinsForClass = (clazz: Class) => mixins.get(clazz);
 
 export const registerMixins = (mixedClass: any, constituents: Function[]) =>
 	mixins.set(mixedClass, constituents);
 
-export const hasMixin = <M>(instance: any, mixin: abstract new (...args) => M): instance is M => {
-	if (instance instanceof mixin)
-		return true;
+export const hasMixin = <M>(
+	instance: any,
+	mixin: abstract new (...args) => M
+): instance is M => {
+	if (instance instanceof mixin) return true;
 
 	const constructor = instance.constructor;
 
@@ -23,14 +24,18 @@ export const hasMixin = <M>(instance: any, mixin: abstract new (...args) => M):
 	while (frontier.size > 0) {
 		// check if the frontier has the mixin we're looking for.  if not, we can say we visited every item in the frontier
 		if (frontier.has(mixin)) return true;
-		frontier.forEach(item => visited.add(item));
+		frontier.forEach((item) => visited.add(item));
 
 		// build a new frontier based on the associated mixin classes and prototype chains of each frontier item
 		const newFrontier = new Set<Function>();
-		frontier.forEach(item => {
-			const itemConstituents = mixins.get(item) ?? protoChain(item.prototype).map(proto => proto.constructor).filter(item => item !== null);
+		frontier.forEach((item) => {
+			const itemConstituents =
+				mixins.get(item) ??
+				protoChain(item.prototype)
+					.map((proto) => proto.constructor)
+					.filter((item) => item !== null);
 			if (itemConstituents)
-				itemConstituents.forEach(constituent => {
+				itemConstituents.forEach((constituent) => {
 					if (!visited.has(constituent) && !frontier.has(constituent))
 						newFrontier.add(constituent);
 				});