Error when used with Storybook 5.3+

[mcookdev]

When I use storybook-readme with the latest Storybook (5.3.x) I receive the following error.

Cannot read property 'theme' of undefined

TypeError: Cannot read property 'theme' of undefined
    at getParameters (http://localhost:6006/vendors~main.bff5a406979c62ca8ff1.bundle.js:113604:63)
    at wrapper (http://localhost:6006/vendors~main.bff5a406979c62ca8ff1.bundle.js:113334:49)
    at http://localhost:6006/vendors~main.bff5a406979c62ca8ff1.bundle.js:18748:14
    at http://localhost:6006/vendors~main.bff5a406979c62ca8ff1.bundle.js:18762:26
    at http://localhost:6006/vendors~main.bff5a406979c62ca8ff1.bundle.js:18272:21
    at http://localhost:6006/vendors~main.bff5a406979c62ca8ff1.bundle.js:19791:14
    at http://localhost:6006/vendors~main.bff5a406979c62ca8ff1.bundle.js:19792:16
    at wrapper (http://localhost:6006/vendors~main.bff5a406979c62ca8ff1.bundle.js:17745:12)
    at http://localhost:6006/vendors~main.bff5a406979c62ca8ff1.bundle.js:18748:14
    at http://localhost:6006/vendors~main.bff5a406979c62ca8ff1.bundle.js:18762:26

This only appears when I use this addon. On the bright side, I figured out a temporary workaround by using:

addParameters({
  options: { theme: {} }
});

We find the plugin to be very useful for our projects and we appreciate your help!

[brandon-pereira]

I'm also getting this error :(

[mcookdev]

I think I figured it out. I was setting a theme using

const theme = create({
  base: "light",
  brandTitle: "My Brand",
  brandUrl: "https://mybrand.com",
  brandImage: "/logo.png"
});

addons.setConfig({
  theme
});

And it should have been:

addParameters({
  options: {
    theme: create({
      base: "light",
      brandTitle: "My Theme",
      brandUrl: "https://mybrand.com",
      brandImage: "/mylogo.png"
    })
  }});

Also, If no custom theme is set, the error does not appear.

[natterstefan]

Hi @mcookdev,

but isn't using manager.js the new of customizing the theme in Storybook@5.3? At least this is what is illustrated in the migration guide 5.2.x -> 5.3.x:

If you are setting storybook options in config.js, especially theme, you should migrate it to manager.js (...) This makes storybook load and use the theme in the manager directly. This allows for richer theming in the future, and has a much better performance!

This would mean this is an issue that should be fixed, right?

https://github.com/tuchk4/storybook-readme/blob/master/packages/storybook-readme/src/services/getParameters.js#L16-L18

This is also explained in the new theming documation: https://storybook.js.org/docs/configurations/theming/