Drop next() as a function parameter type on action listener

[M1kep]

Description

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What type of issue is this? (place an x in one of the [ ])

• [x] bug
• [ ] enhancement (feature request)
• [x] question
• [ ] documentation related
• [ ] example code related
• [ ] testing related
• [ ] discussion

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• [x] I've read and understood the Contributing guidelines and have done my best effort to follow them.
• [x] I've read and agree to the Code of Conduct.
• [x] I've searched for any related issues and avoided creating a duplicate issue.

---

Bug Report

Filling out the following details about bugs will help us solve your issue sooner.

Reproducible in:

package version: 3.11.0

node version: 16.15.0

OS version(s): Docker - node:16-alpine

Steps to reproduce:

1. Create an action listener on an App instance and call next()

            // Log action_ids of all actions when in Debug mode
            bot.appInstance?.action(/.*/, async ({ action, logger, next }) => {
                if ('action_id' in action) {
                    logger.debug(`Action Hit(${botName}): ${action.action_id}`);
                }
                await next();
            });

Expected result:

Either TypeScript does not provide next as a valid parameter, or next to exist.

Actual result:

Error:

[ERROR]  bolt-app UnknownError: next is not a function
    at asCodedError (/workspace/.yarn/cache/@slack-bolt-npm-3.11.0-1183767d75-25491d656e.zip/node_modules/@slack/bolt/src/errors.ts:56:10)
    at App.handleError (/workspace/.yarn/cache/@slack-bolt-npm-3.11.0-1183767d75-25491d656e.zip/node_modules/@slack/bolt/src/App.ts:1049:37)
    at App.processEvent (/workspace/.yarn/cache/@slack-bolt-npm-3.11.0-1183767d75-25491d656e.zip/node_modules/@slack/bolt/src/App.ts:1032:19)
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at async SocketModeClient.<anonymous> (/workspace/.yarn/cache/@slack-bolt-npm-3.11.0-1183767d75-25491d656e.zip/node_modules/@slack/bolt/src/receivers/SocketModeReceiver.ts:218:9) {
  code: 'slack_bolt_unknown_error',
  original: TypeError: next is not a function
      at /workspace/src/core/botManager.ts:64:23
      at /workspace/.yarn/cache/@slack-bolt-npm-3.11.0-1183767d75-25491d656e.zip/node_modules/@slack/bolt/src/App.ts:1006:27
      at invokeMiddleware (/workspace/.yarn/cache/@slack-bolt-npm-3.11.0-1183767d75-25491d656e.zip/node_modules/@slack/bolt/src/middleware/process.ts:32:12)
      at next (/workspace/.yarn/cache/@slack-bolt-npm-3.11.0-1183767d75-25491d656e.zip/node_modules/@slack/bolt/src/middleware/process.ts:24:21)
      at Array.<anonymous> (/workspace/.yarn/cache/@slack-bolt-npm-3.11.0-1183767d75-25491d656e.zip/node_modules/@slack/bolt/src/middleware/builtin.ts:197:11)
      at invokeMiddleware (/workspace/.yarn/cache/@slack-bolt-npm-3.11.0-1183767d75-25491d656e.zip/node_modules/@slack/bolt/src/middleware/process.ts:23:47)
      at next (/workspace/.yarn/cache/@slack-bolt-npm-3.11.0-1183767d75-25491d656e.zip/node_modules/@slack/bolt/src/middleware/process.ts:24:21)
      at Array.onlyActions (/workspace/.yarn/cache/@slack-bolt-npm-3.11.0-1183767d75-25491d656e.zip/node_modules/@slack/bolt/src/middleware/builtin.ts:42:9)
      at invokeMiddleware (/workspace/.yarn/cache/@slack-bolt-npm-3.11.0-1183767d75-25491d656e.zip/node_modules/@slack/bolt/src/middleware/process.ts:23:47)
      at processMiddleware (/workspace/.yarn/cache/@slack-bolt-npm-3.11.0-1183767d75-25491d656e.zip/node_modules/@slack/bolt/src/middleware/process.ts:35:10)

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[srajiang]

@M1kep - The error message you are seeing is expected. next is not supplied as args to your action listener callback function. You do not explicitly have to call next in this case for other listeners you register to execute.

There is a way to define a listener middleware. Here is thedocumentation for that and the way to use next within the context of listener middleware. It may be suitable for your use case, I don't have enough detail on what you're trying to do to know for sure!

[M1kep]

If the action listener callback function is not supplied next as an arg, I'd think the type definition for that call wouldn't provide it in the list of available args?

[srajiang]

That I'd need to look further into. Thanks for clarifying, I'll take a look at what's going on with the type definition there...

[filmaj]

I've tweaked the title and labels in this issue to have this issue focus on improving the types in this situation.