From 250e55b0d98d0855ede51ca6245cecd559b299ed Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Thu, 20 Sep 2018 22:43:44 +0200
Subject: [PATCH 1/3] Ensure that all event properties are included, even if no
 (internal) listeners are registered, when re-dispatching events to the DOM
 (PR 10019 follow-up)

---
 web/ui_utils.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/web/ui_utils.js b/web/ui_utils.js
index d0e59d58d..c0c11f277 100644
--- a/web/ui_utils.js
+++ b/web/ui_utils.js
@@ -708,12 +708,13 @@ class EventBus {
     let eventListeners = this._listeners[eventName];
     if (!eventListeners || eventListeners.length === 0) {
       if (this._dispatchToDOM) {
-        this._dispatchDOMEvent(eventName);
+        const args = Array.prototype.slice.call(arguments, 1);
+        this._dispatchDOMEvent(eventName, args);
       }
       return;
     }
     // Passing all arguments after the eventName to the listeners.
-    let args = Array.prototype.slice.call(arguments, 1);
+    const args = Array.prototype.slice.call(arguments, 1);
     // Making copy of the listeners array in case if it will be modified
     // during dispatch.
     eventListeners.slice(0).forEach(function (listener) {

From f317a2cb40813a5dde2942266b55559be53b868d Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Thu, 20 Sep 2018 23:08:38 +0200
Subject: [PATCH 2/3] Ensure that the DOM event listeners are removed at the
 end of the relevant `EventBus` unit-tests, to prevent the tests from
 interfering with each other

---
 test/unit/ui_utils_spec.js | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/test/unit/ui_utils_spec.js b/test/unit/ui_utils_spec.js
index 4ba2a22e0..eab665fe1 100644
--- a/test/unit/ui_utils_spec.js
+++ b/test/unit/ui_utils_spec.js
@@ -272,13 +272,17 @@ describe('ui_utils', function() {
       eventBus.on('test', function() {
         count++;
       });
-      document.addEventListener('test', function() {
-        count++;
-      });
+      function domEventListener() {
+        done.fail('shall not dispatch DOM event.');
+      }
+      document.addEventListener('test', domEventListener);
+
       eventBus.dispatch('test');
 
       Promise.resolve().then(() => {
         expect(count).toEqual(1);
+
+        document.removeEventListener('test', domEventListener);
         done();
       });
     });
@@ -291,13 +295,17 @@ describe('ui_utils', function() {
       eventBus.on('test', function() {
         count++;
       });
-      document.addEventListener('test', function() {
+      function domEventListener() {
         count++;
-      });
+      }
+      document.addEventListener('test', domEventListener);
+
       eventBus.dispatch('test');
 
       Promise.resolve().then(() => {
         expect(count).toEqual(2);
+
+        document.removeEventListener('test', domEventListener);
         done();
       });
     });

From 39776168a263b79837058c8a1a08b192bae84788 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Fri, 21 Sep 2018 14:12:01 +0200
Subject: [PATCH 3/3] Add `EventBus` unit-tests to ensure that the (optional)
 argument handling works correctly

---
 test/unit/ui_utils_spec.js | 48 ++++++++++++++++++++++++++++++++++----
 1 file changed, 44 insertions(+), 4 deletions(-)

diff --git a/test/unit/ui_utils_spec.js b/test/unit/ui_utils_spec.js
index eab665fe1..145b30d6a 100644
--- a/test/unit/ui_utils_spec.js
+++ b/test/unit/ui_utils_spec.js
@@ -182,12 +182,25 @@ describe('ui_utils', function() {
     it('dispatch event', function () {
       var eventBus = new EventBus();
       var count = 0;
-      eventBus.on('test', function () {
+      eventBus.on('test', function(evt) {
+        expect(evt).toEqual(undefined);
         count++;
       });
       eventBus.dispatch('test');
       expect(count).toEqual(1);
     });
+    it('dispatch event with arguments', function() {
+      const eventBus = new EventBus();
+      let count = 0;
+      eventBus.on('test', function(evt) {
+        expect(evt).toEqual({ abc: 123, });
+        count++;
+      });
+      eventBus.dispatch('test', {
+        abc: 123,
+      });
+      expect(count).toEqual(1);
+    });
     it('dispatch different event', function () {
       var eventBus = new EventBus();
       var count = 0;
@@ -269,7 +282,8 @@ describe('ui_utils', function() {
       }
       const eventBus = new EventBus();
       let count = 0;
-      eventBus.on('test', function() {
+      eventBus.on('test', function(evt) {
+        expect(evt).toEqual(undefined);
         count++;
       });
       function domEventListener() {
@@ -292,10 +306,12 @@ describe('ui_utils', function() {
       }
       const eventBus = new EventBus({ dispatchToDOM: true, });
       let count = 0;
-      eventBus.on('test', function() {
+      eventBus.on('test', function(evt) {
+        expect(evt).toEqual(undefined);
         count++;
       });
-      function domEventListener() {
+      function domEventListener(evt) {
+        expect(evt.detail).toEqual({});
         count++;
       }
       document.addEventListener('test', domEventListener);
@@ -305,6 +321,30 @@ describe('ui_utils', function() {
       Promise.resolve().then(() => {
         expect(count).toEqual(2);
 
+        document.removeEventListener('test', domEventListener);
+        done();
+      });
+    });
+    it('should re-dispatch to DOM, with arguments (without internal listeners)',
+        function(done) {
+      if (isNodeJS()) {
+        pending('Document in not supported in Node.js.');
+      }
+      const eventBus = new EventBus({ dispatchToDOM: true, });
+      let count = 0;
+      function domEventListener(evt) {
+        expect(evt.detail).toEqual({ abc: 123, });
+        count++;
+      }
+      document.addEventListener('test', domEventListener);
+
+      eventBus.dispatch('test', {
+        abc: 123,
+      });
+
+      Promise.resolve().then(() => {
+        expect(count).toEqual(1);
+
         document.removeEventListener('test', domEventListener);
         done();
       });