respond support in view_submission listeners (it works only when response_url_enabled is true)

[mogadanez]

Description

included block into my modal:

{
			"block_id": "my_block_id",
			"type": "input",
			"optional": true,
			"label": {
				"type": "plain_text",
				"text": "Select a channel to post the result on"
			},
			"element": {
				"action_id": "my_action_id",
				"type": "conversations_select",
				"default_to_current_conversation": true,
				"response_url_enabled": true
			}
		}

body payload have response_urls array, but respond function is not available
What is best practice to post delayed response after modal submission?

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.

[seratch]

The response_url_enabled is a relatively new option and unfortunately, Bolt for JS doesn't support it yet.

At this point, a possible workaround would be:

// @slack/web-api already depends on axios
const axios = require('axios');

const responseUrls = body.response_urls;
if (responseUrls && responseUrls.length > 0) {
  const url = responseUrls[0].response_url;
  const stateValues = body.view.state.values;
  await axios.post(url, { text: "```" + JSON.stringify(stateValues) + "```" });
}

Also, here is a working example in TypeScript:

• https://github.com/seratch/bolt-starter-ts/blob/748542ae657a4a49c4f558d194f549969368a205/src/index.ts#L47
• https://github.com/seratch/bolt-starter-ts/blob/748542ae657a4a49c4f558d194f549969368a205/src/simpleModal.ts#L82-L87

[seratch]

We will implement respond for view submissions in Python first. slackapi/bolt-python#260