How to respond to Modal's view_submission events

Description

The documentation mentions in several places (1, 2, 3) that when a modal is submitted, you get a view_submission payload. But I can’t find anything on how you get the payload - it doesn’t seem to be an app.event() or app.action() based one. I can’t find any example code either.

I’ve tried tons of things like:

app.event('view_submission', async (everything: any) => {
    everything.ack();
    console.log("I'm here");
});

But the callback never triggers. I always get a

[ERROR]  bolt-app An incoming event was not acknowledged within 3 seconds. Ensure that the ack() argument is called in a listener.

Stranger still, the Events API doesn’t contain anything about view_submission either, but the Error confirms it is an event.

So my question is - How are you supposed to respond to a Modal submit using Bolt?

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

• bug
• enhancement (feature request)
• question
• documentation related
• testing related
• discussion

Requirements (place an x in each of the [ ])

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

[paragbaxi]

also ran into this. would appreciate it if it was part of javascript bolt docs (or if i missed it, more prominently shown?)

[dginovker]

THANK YOU!!! The callback_id was the missing piece. For future readers, it’s needed in the first level of the view JSON, i.e. your JSON looks like this:

view: {
  "title": ...,
  "submit": ...,
  "blocks": [...],
  "type": "modal",
  "callback_id": "a_unique_id",
}

Then you can respond to it with:

app.view('a_unique_id', async (everything) => {
  everything.ack();
});