slash-command-dialog.js

const http = require('http');
const express = require('express');
const app = express();
const bodyParser = require('body-parser');
const { WebClient } = require('@slack/client');
const { createMessageAdapter } = require('@slack/interactive-messages');

const slack = new WebClient(process.env.SLACK_ACCESS_TOKEN);
const slackInteractions = createMessageAdapter(process.env.SLACK_SIGNING_SECRET);

const orderAction = 'coffee_order';

// handle slash command
app.post('/slack/command', bodyParser.urlencoded({ extended: false }), (req, res) => {
  // should verify signature, but skipping for demo purposes
  console.log('received slash command');
  res.send('');
  
  // asynchronously open a dialog
  process.nextTick(() => {
    slack.dialog.open({
      trigger_id: req.body.trigger_id,
      dialog: {
        title: 'Create coffee order',
        callback_id: orderAction,
        elements: [{
          type: 'text',
          name: 'details',
          label: 'Details',
        }],
        state: 'hello'
      },
      submit_label: 'Order',
    });
  });
});

// handle dialog submission
slackInteractions.action(orderAction, (payload, respond) => {
  console.log('received dialog submission');
  console.log(payload);
  
  // asynchronously send a success message
  process.nextTick(() => {
    respond({
      text: 'Order recieved',
    });
  });
});
app.use('/slack/actions', slackInteractions.expressMiddleware());

const server = http.createServer(app);
server.listen(3000);