Support babel.config.ts

[evanpurkhiser]

Is your feature request related to a problem? Please describe
Storybook is unable to load babel.config.ts (note ts, not js). It looks like it's explicitly not included here

storybook/lib/core-common/src/utils/load-custom-babel-config.ts

Lines 80 to 84 in 7064642

	loadFromPath(path.resolve(configDir, '.babelrc')) ||
	loadFromPath(path.resolve(configDir, '.babelrc.json')) ||
	loadFromPath(path.resolve(configDir, '.babelrc.js')) ||
	loadFromPath(path.resolve(configDir, 'babel.config.json')) ||
	loadFromPath(path.resolve(configDir, 'babel.config.js'));

I've

Describe the solution you'd like
Support automatic discovery of babel.config.ts and .babelrc.ts

Describe alternatives you've considered
Currently I load the babel config in my main.ts using the babel prop.

Which also I've noticed, is documented here, but is not included in the StorybookConfig type, so I end up with a // @ts-expect-error.

Are you able to assist to bring the feature to reality?
If it makes sense to add to the aforementioned list, I can open a PR.

Additional context
The PR where I ran into this issue: getsentry/sentry#26918

[shilman]

I think we're going the other way towards forcing everybody to use the .storybook/main.js babel configuration instead (which should support this usage but requires a line of configuration on the user's part). @ndelangen should be able to share more.

[evanpurkhiser]

That sounds good.

which should support this usage

It does work right now, but the type is missing for the babel option in main and requires as @ts-expect-error.

[shilman]

Jiminy cricket!! I just released https://github.com/storybookjs/storybook/releases/tag/v6.4.0-alpha.33 containing PR #15928 that references this issue. Upgrade today to the @next NPM tag to try it out!

npx sb upgrade --prerelease

Closing this issue. Please re-open if you think there's still more to do.