fix(ts): action can be an async function

[prokopsimek]

Since we can use parseAsync for async functions so the action can be asynchronous.

related to #806

Pull Request

Problem

Promise returned in function argument where a void return was expected.eslint(@typescript-eslint/no-misused-promises)

Solution

add Promise<void> to the action argument

• TypeScript typings

ChangeLog

[shadowspawn]

Thanks.

Would you like to add an example usage to typings/commander-tests.ts? (This file is compiled to check for errors, but not run.)

[prokopsimek]

@shadowspawn Hi, I'll add the test tomorrow :)

[shadowspawn]

Thanks @prokopsimek
We have changes for a v5 underway, but I am thinking we will release this in a v4 patch too as was not as intended ( I missed the TypeScript changes to the action handler when adding .parseAsync()).

[shadowspawn]

Reproduced by running eslint on command line (warnings within editor somewhat confused).

[abetomo]

Thank you!

[shadowspawn]

This has been released:
https://github.com/tj/commander.js/releases/tag/v4.1.1