Add types of state.values on modal submission

[dan-kez]

Description

I am currently working on validating modal submissions from Slack. Somewhat unfortunately all block types carry their value under different keys (e.g. rather than all having a value key there are selected_users, selected_channel, selected_options and more).

So far I have been unable to find documentation about the variety of response type structures that input blocks can have on modal submission.

I noticed there is a TODO comment here:

bolt-js/src/types/view/index.ts

Line 87 in 2ab6467

[actionId: string]: any; // TODO: a union of all the input elements' output payload

I am happy to submit a PR with a union type for this response if someone can point me to docs on what is available from the API. For my own bot, I have had to step through with a debugger to introspect the responses.

As a follow up, it would be amazing if there was a way to get simplified response schema from the slack's response (e.g. get a block_id: value mapping or some relative equivalent that includes the action_id). This would make it much easier to quickly write any schema validation using tools like https://github.com/jquense/yup or https://hapi.dev/module/joi/ without having to massage the data into a flatter form.

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• enhancement (feature request)
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[seratch]

As I mentioned here: #404 (comment), I'm always happy to provide more types for TypeScript users.

@stevengill @aoberoi
Do you have thoughts about this?

[aoberoi]

I love it! One suggestion: we could add the type definitions for the outputs of the actions closer to the definitions of the action blocks/elements themselves if they were put in the @slack/types package. That also would make them more reusable outside of Bolt for JS.

[aoberoi]

As a follow up, it would be amazing if there was a way to get simplified response schema from the slack's response (e.g. get a block_id: value mapping or some relative equivalent that includes the action_id).

This sounds like a neat idea, but I don't think I completely understand. It sounds like you want to validate the action payload you receive from Slack fits a schema you have in your application, is that right? If so, I'm not sure how this would help in an application, but maybe you can walk me through it.

I can see some value in a simplified mapping that works across all action block/element types. One benefit would be that you could deal with all actions is some generic way, which would allow you to have more code reuse. The biggest challenge I see is modeling the selection values. For example, a 'user_select' element has a single string value (called 'selected_user') and a 'multi_user_selet' element has an array of string values (called 'selected_users'). So would we wrap all values as an array to keep them fitting the same schema? For example: { "my_block_id" : ["U12345"] }. I think reading the value by always indexing [0] on the array would be a little ugly. Any thoughts on how you would do this?