#19

frontend/src/lib/eventBus/EventBus.ts

@@ -0,0 +1,35 @@
+export class EventBus<T>
+{
+  private value:        T
+  private subscribers:  ((val: T) => void)[]  = []
+
+  constructor (
+      initialValue: T)
+  {
+    this.value = initialValue
+  }
+
+  get ()
+  : T
+  {
+    return this.value
+  }
+
+  set (
+      val:  T)
+  : void
+  {
+    this.value = val
+    this.subscribers.forEach (f => f (val))
+  }
+
+  subscribe (
+      func: (val: T) => void)
+  : () => void
+  {
+    this.subscribers.push (func)
+    return () => {
+      this.subscribers = this.subscribers.filter (sub => sub !== func)
+    }
+  }
+}

frontend/src/lib/eventBus/WikiIdBus.ts

@@ -0,0 +1,3 @@
+import { EventBus } from './EventBus'
+
+export const WikiIdBus = new EventBus<number | null> (null)