start

utils/eventBus.js

@@ -0,0 +1,20 @@
+export default function createBus() {
+  return {
+    events: {},
+    on(event, callback) {
+      if (!this.events[event]) this.events[event] = [];
+      this.events[event].push(callback);
+    },
+    off(event, callback) {
+      if (!this.events[event]) return;
+      if (!callback) this.events[event] = [];
+      else {
+        const index = this.events[event].indexOf(callback);
+        if (index !== -1) this.events[event].splice(index, 1);
+      }
+    },
+    emit(event, ...args) {
+      if (this.events[event]) this.events[event].forEach((callback) => callback(...args));
+    },
+  };
+}