Props: Fix typescript unspecified default value

[shilman]

Issue: #9827

What I did

Mapping a function that takes two arguments passes the index as the second argument. Fixed & tested!

How to test

See updated snapshots & chromatic changes

[patricklafrance]

Is it really the following line that fix the issue?

https://github.com/storybookjs/storybook/pull/9873/files#diff-3211380902a8842f1636fd47078eeb11L26

[shilman]

@patricklafrance Yes, AFAICT. i'm not familiar with your code yet, so perhaps there's a better fix elsewhere. the rest of the PR is just updated (fixed) snapshots

[patricklafrance]

I don't understand how it could be the problem.

Furthermore if the user is not using react-docgen for TS, he doesn't go through this code. I can't find which version of SB he is running, is he on an alpha version with react-docgen?

[shilman]

@patricklafrance You don't need to know anything about the user's setup for this. The problem is repro'd multiple times in the snapshot tests, and the fix appears to be working. What am I missing?

[patricklafrance]

@shilman

Unless you are using react-docgen, the "typescript" codepath shouldn't be followed because it's based on the name of the type property.

In react-docgen, you have the following:

• type -> propTypes path
• tsType -> typescript path
• flowType -> flow path

https://github.com/reactjs/react-docgen#result-data-structure

When using react-docgen for propTypes and react-doc-typescript you get type for both so the code always go through the "propTypes" codepath.

Overall if it fix a bug I don't mind, I am asking because I don't understand how it could fix something.

[shilman]

Does that mean that the typescript handling code is basically unused in 5.3?

[patricklafrance]

@shilman unless something changes after my last commit, YES.

It was going to be used once I rework the docs presets to include react-docgen-typescript-loader and provide a default config that would set typePropName to tsType.