Merge commit 'f8bb37e12f96c86bb44a53ac28d06cc522cf7ab9' as 'backend'

backend/src/helpers/sync.ts

@@ -0,0 +1,33 @@
+import { Types } from "mongoose";
+import { Observer, Subject } from "rxjs";
+
+export interface SyncEvent {
+    type: string
+}
+
+class SyncHelper {
+    private userSubjects = new Map<string, Subject<SyncEvent>>()
+    public subscribe(uid: Types.ObjectId, observer: Observer<SyncEvent> | ((value: SyncEvent) => void)) {
+        const uid_s = uid.toString()
+        if (!this.userSubjects.has(uid_s)) {
+            this.userSubjects.set(uid_s, new Subject())
+        }
+        return this.userSubjects.get(uid_s).asObservable().subscribe(observer)
+    }
+
+    public next(uid: Types.ObjectId, value: SyncEvent) {
+        const uid_s = uid.toString()
+        if (this.userSubjects.has(uid_s)) {
+            this.userSubjects.get(uid_s).next(value)
+        }
+    }
+
+    nextEach(value: SyncEvent) {
+        this.userSubjects.forEach(v => {
+            v.next(value)
+        })
+    }
+
+}
+
+export default new SyncHelper();