From 14ef31483f9d891f3bd7920757c015bdd11da498 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=A9ry=20Debongnie?= <ged@odoo.com>
Date: Sun, 3 Feb 2019 13:56:36 +0100
Subject: [PATCH] throw error if missing callback in event bus

---
 web/static/src/ts/core/event_bus.ts                      | 3 +++
 web/static/tests/core/{bus_test.ts => event_bus.test.ts} | 8 ++++++++
 2 files changed, 11 insertions(+)
 rename web/static/tests/core/{bus_test.ts => event_bus.test.ts} (83%)

diff --git a/web/static/src/ts/core/event_bus.ts b/web/static/src/ts/core/event_bus.ts
index 23b903ad..5a224f87 100644
--- a/web/static/src/ts/core/event_bus.ts
+++ b/web/static/src/ts/core/event_bus.ts
@@ -35,6 +35,9 @@ export class EventBus {
    * listener.
    */
   on(eventType: string, owner: any, callback: Callback) {
+    if (!callback) {
+      throw new Error("Missing callback");
+    }
     if (!this.subscriptions[eventType]) {
       this.subscriptions[eventType] = [];
     }
diff --git a/web/static/tests/core/bus_test.ts b/web/static/tests/core/event_bus.test.ts
similarity index 83%
rename from web/static/tests/core/bus_test.ts
rename to web/static/tests/core/event_bus.test.ts
index 45f6efe7..4cb74ae6 100644
--- a/web/static/tests/core/bus_test.ts
+++ b/web/static/tests/core/event_bus.test.ts
@@ -20,6 +20,14 @@ describe("event bus behaviour", () => {
     bus.trigger("event");
   });
 
+  test("throw error if callback is undefined", () => {
+    expect.assertions(1);
+    const bus = new EventBus();
+    expect(() => bus.on("event", {}, <any>undefined)).toThrow(
+      `Missing callback`
+    );
+  });
+
   test("can unsubscribe", () => {
     const bus = new EventBus();
     let notified = false;