example of a bolt listener middleware that catches errors in view submission handlers and pushes a view

example-listener-middleware.js

import { App } from '@slack/bolt';

const app = new App(...);

// a listener middleware.
// could easily be shared. can be refactored into a global middleware too.
function pushViewOnErrors(errorViewTemplate) {
  return async function _pushViewOnErrors({ body, client, logger, ack, next }) => {
    try {
      await next();
    } catch (error) {
      logger.info('pushViewOnErrors: error caught');
      
      // acknowledge the submission in case the listener hadn't yet done so
      await ack();
      
      // push the view
      await client.views.push({
        trigger_id: body.trigger_id,
        view: errorView(error),
      });
      
      logger.info('pushViewOnErrors: view pushed');
    }
  }
}

// a view template, maybe built with slack-block-builder ;)
const myErrorViewTemplate = (error) => {
  // ...
};

app.view({ callback_id: 'cid', type: 'view_submission' }, pushViewOnErrors(myErrorViewTemplate), ({ view }) => {
  // ...
  // At runtime, something bad will happen, and it with throw!
  // when that happens, the error view will be pushed on
  throw Error('oh no!');
});

(async () => {
  await app.start(3000);
  console.log('app is running');
})();