Addon-docs: Hide React default props in source block

[zeckdude]

Issue: #11510

What I did

Added option to not show default props on code preview when a component isn't overriding those values. In jsxDecorator.tsx, it is using the reactElementToString method from the react-element-to-jsx-string package. If you check their options, they accept a showDefaultProps property, which when set to false omits the default props in the JSX. This sets that to false so it doesn't show the default props by default.

How to test

• Is this testable with Jest or Chromatic screenshots?
  Yes. I added a test case, but it looks like it is failing due to a snapshot. I'm not familiar with snapshots, so I could use some help there please.
• Does this need a new example in the kitchen sink apps?
  No
• Does this need an update to the documentation?
  Yeah I think so, but I'm struggling determining where that would be added the best. Any advice?

If your answer is yes to any of these, please make sure to include it in your PR.

[shilman]

LGTM. Thanks for tracking this down @zeckdude

[Greenheart]

Thank you for fixing this @zeckdude! This has been one of the few issues my team have had with Storybook since we upgraded to v6, and thanks to your PR we'll get a really smooth DX with relevant code samples in docs.

Keep up the good work with the 6.1.0 release! ✨

[shleewhite]

@zeckdude does this work with typescript? instead of setting Component.defaultProps, we just depend on the type.

[zeckdude]

@shleewhite It currently has nothing to do with TS but I'm sure that could be included. Which type would it be looking for to determine that it is a component?

[shleewhite]

@zeckdude our components are written like this:

export type componentProps = {
  propA?: string,
};

export const myComponent = React.functionComponent<componentProps>(
  {
       propA = 'Sample Text',
  }
) => (
   <div>{propA}</div>
)

So I'd want the source code for the story to just show:<myComponent /> if I don't pass a value.

[victor-grajski]

+1 to @shleewhite !