@storybook/addon-storyshots supports only main.js

Describe the bug

The getMainFile method of the storyshots addon has a hardcoded name for the new configuration style for version 5.3 of main.js. This prevents usage of TypeScript, for example, where the file is main.ts.

You can see the file name here: https://github.com/storybookjs/storybook/blob/76c3f3a6403aeeac6175a4d086c7b35c087f0d52/addons/storyshots/storyshots-core/src/frameworks/configure.ts#L47

It seems the getPreviewFile method correctly supports both JS and TS files.

This results in storyshots failing with storyshots found 0 stories.

If I edit this method to also include TS files, it seems to start working again:

const getMainFile = (configDir: string): string | false => {
  const main = path.join(configDir, 'main.js');
  const mainTS = path.join(configDir, 'main.ts');

  if (isFile(main)) {
    return main;
  }

  if (isFile(mainTS) {
    return mainTS;
  }

  return false;
};

[iiroj]

Cool, working now!

Although it seems only module.exports works, when using export default causes no configuration to be found.

[shilman]

So main.ts works – played around with it yesterday – tho AFAICT support for it is entirely accidental. @mrmckeb and I played around for a few minutes and couldn’t figure out WHY it works (that serverRequire is doing something tricky cc @igor-dv ). At any rate, will merge the fix. Thanks @iiroj !!!