Description

I tried following the examples given in the example documentation to open a modal, and it did not work and produced an error invalid_arguments

After digging a bit, the actual error explanation returned was

[ERROR] must define submit to use input block [json-pointer:/view/blocks/0/input]

It seems opening a modal via web.views.open(openModalPayload) requires the payload to have a submit field to work and will crash otherwise

This should be updated in the documentation (especially the "getting started" examples

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.

Bug Report

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

Packages:

Select all that apply:

• @slack/web-api
• @slack/events-api
• @slack/interactive-messages
• @slack/rtm-api
• @slack/webhooks
• I don't know

Reproducible in:

package version: @slack/web-api@^5.1.0", "@slack/web-api@^5.2.0"

node version: v11.5.0

Steps to reproduce:

1. Start a nodejs app
2. Follow the example given in the documentation to open a modal and copy the code to your own app
3. Run the code up till this point

Expected result:

Expected the example to work

Actual result / Attachment

{ Error: An API error occurred: invalid_arguments
    at Object.platformErrorFromResult (/.../node_modules/@slack/web-api/src/errors.ts:94:5)
    at WebClient.apiCall (/.../node_modules/@slack/web-api/src/WebClient.ts:159:13)
    at process.internalTickCallback (internal/process/next_tick.js:77:7)
  code: 'slack_webapi_platform_error',
  data:
   { ok: false,
     error: 'invalid_arguments',
     response_metadata: { messages: [Array], scopes: [Array] } } }
{ messages:
   [ '[ERROR] must define `submit` to use `input` block [json-pointer:/view/blocks/0/input]' ],