add MessageReaction to ActivityHandler (#1038)

Author: johnataylor

libraries/botbuilder-core/src/activityHandler.ts

@@ -108,6 +108,37 @@ export class ActivityHandler {
         return this.on('MembersRemoved', handler);
     }
 
+    /**
+     * Receives only MessageReaction activities, regardless of whether message reactions were added or removed
+     * @remarks
+     * MessageReaction activities are sent to the bot when a message reacion, such as 'like' or 'sad' are
+     * associated with an activity previously sent from the bot.
+     * @param handler BotHandler A handler function in the form async(context, next) => { ... }
+     */
+    public onMessageReaction(handler: BotHandler): this {
+        return this.on('MessageReaction', handler);
+    }
+
+    /**
+     * Receives only MessageReaction activities representing message reactions being added.
+     * @remarks
+     * context.activity.reactionsAdded will include at least one entry.
+     * @param handler BotHandler A handler function in the form async(context, next) => { ... }
+     */
+    public onReactionsAdded(handler: BotHandler): this {
+        return this.on('ReactionsAdded', handler);
+    }
+
+    /**
+     * Receives only MessageReaction activities representing message reactions being removed.
+     * @remarks
+     * context.activity.reactionsRemoved will include at least one entry.
+     * @param handler BotHandler A handler function in the form async(context, next) => { ... }
+     */
+    public onReactionsRemoved(handler: BotHandler): this {
+        return this.on('ReactionsRemoved', handler);
+    }
+
     /**
      * Receives all Event activities.
      * @remarks
@@ -216,6 +247,17 @@ export class ActivityHandler {
                         }
                     });
                     break;
+                case ActivityTypes.MessageReaction:
+                    await this.handle(context, 'MessageReaction', async () => {
+                        if (context.activity.reactionsAdded && context.activity.reactionsAdded.length > 0) {
+                            await this.handle(context, 'ReactionsAdded', runDialogs);
+                        } else if (context.activity.reactionsRemoved && context.activity.reactionsRemoved.length > 0) {
+                            await this.handle(context, 'ReactionsRemoved', runDialogs);
+                        } else {
+                            await runDialogs();
+                        }
+                    });
+                    break;
                 case ActivityTypes.Event:
                     await this.handle(context, 'Event', async () => {
                         if (context.activity.name === 'tokens/response') {

libraries/botbuilder-core/tests/ActivityHandler.test.js

@@ -133,6 +133,45 @@ describe('ActivityHandler', function() {
         processActivity({type: ActivityTypes.ConversationUpdate, membersRemoved: [{id: 1}]}, bot);
     });
 
+    it(`should fire onMessageReaction`, async function (done) {
+
+        const bot = new ActivityHandler();
+
+        bot.onMessageReaction(async(context, next) => {
+            assert(true, 'onMessageReaction not called');
+            done();
+            await next();
+        });
+
+        processActivity({type: ActivityTypes.MessageReaction}, bot);
+    });
+
+    it(`should fire onReactionsAdded`, async function (done) {
+
+        const bot = new ActivityHandler();
+
+        bot.onReactionsAdded(async(context, next) => {
+            assert(true, 'onReactionsAdded not called');
+            done();
+            await next();
+        });
+
+        processActivity({type: ActivityTypes.MessageReaction, reactionsAdded: [{type: 'like'}]}, bot);
+    });
+
+    it(`should fire onReactionsRemoved`, async function (done) {
+
+        const bot = new ActivityHandler();
+
+        bot.onReactionsRemoved(async(context, next) => {
+            assert(true, 'onReactionsRemoved not called');
+            done();
+            await next();
+        });
+
+        processActivity({type: ActivityTypes.MessageReaction, reactionsRemoved: [{type: 'like'}]}, bot);
+    });
+    
     it(`should fire onEvent`, async function (done) {
 
         const bot = new ActivityHandler();