Create Observer.js

Author: goodcodd

patterns/observer_pattern/Observer.js

@@ -0,0 +1,16 @@
+class Observer {
+  constructor() {
+    this.observers = [];
+  }
+  subscribe(fn) {
+    this.observers.push(fn);
+  }
+  unsubscribe(fn) {
+    this.observers = this.observers.filter(
+      (observer) => observer !== fn
+    );
+  }
+  notify(data) {
+    this.observers.forEach((observer) => observer(data));
+  }
+}