bot.js

const slackConfig = {
  // YOUR CONFIG GOES HERE
};
const adapter = new SlackAdapter(slackConfig);

// Use SlackEventMiddleware to emit events that match their original Slack event types.
adapter.use(new SlackEventMiddleware());
// Use SlackMessageType middleware to further classify messages as direct_message,
// direct_mention, or mention.
adapter.use(new SlackMessageTypeMiddleware());
// HACK write our own middleware to handle new format of messages received from Slack.
adapter.use(new SlackHackMiddleware());

const controller = new Botkit({
    webhook_uri: '/api/messages',
    adapter: adapter,
    storage,
});

SlackHackMiddleware.js

"use strict";

// ADAPTED FROM: botbuilder-adapter-slack/lib/messagetype_middleware.js

var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
    return new (P || (P = Promise))(function (resolve, reject) {
        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
        step((generator = generator.apply(thisArg, _arguments || [])).next());
    });
};
Object.defineProperty(exports, "__esModule", { value: true });
const botbuilder_1 = require("botbuilder");

/**
 * This hackish middleware enables BotKit developers using the BotBuilder SlackAdapter class to
 * use Slack App-created bots. These new bots send different event types than legacy bots. Without
 * an update like this any controller.hears() in your bots won't be triggered as the 'text' attribute
 * isn't set and the botkitEventType isn't something recognizable, e.g. 'direct_mention' instead of
 * the 'app_mention' value that is now sent.
 *
 * NB: this isn't a complete implementation, it's just enough to get you started with a new-style
 * Slack bot. Ultimately I expect this functionality to land in the official Slack adapter / middleware.
 * Use that once it's available.
 */
class SlackHackMiddleware extends botbuilder_1.MiddlewareSet {
    /**
     * Not for direct use - implements the MiddlewareSet's required onTurn function used to process the event
     * @param context
     * @param next
     */
    onTurn(context, next) {
        return __awaiter(this, void 0, void 0, function* () {
            if (context.activity.type === 'event' && context.activity.channelData) {
                let adapter = context.adapter;
                const bot_user_id = yield adapter.getBotUserByTeam(context.activity);
                var mentionSyntax = '<@' + bot_user_id + '(\\|.*?)?>';
                var mention = new RegExp(mentionSyntax, 'i');
                var direct_mention = new RegExp('^' + mentionSyntax, 'i');

                if (context.activity.channelData.type === 'app_mention') {
                    context.activity.text = context.activity.channelData.text
                        .replace(direct_mention, '')
                        .replace(/^\s+/, '')
                        .replace(/^:\s+/, '')
                        .replace(/^\s+/, '')
                    ;
                    context.activity.channelData.botkitEventType = 'direct_mention';

                }
                
                // Ignore bot_messages; switch the botkit event type to 'bot_message'
                // and the activity type to 'event' (stops it from being included in dialogs).
                if (context.activity.channelData && context.activity.channelData.bot_id) {
                    context.activity.channelData.botkitEventType = 'bot_message';
                    context.activity.type = botbuilder_1.ActivityTypes.Event;
                }
            }

            yield next();
        });
    }
}

exports.SlackHackMiddleware = SlackHackMiddleware;