Support for defaultProps will be removed from function components in a future major release.

[ochavarria2u]

Feedback summary

Using React 18 I started to notice these warning messages for default props.
Warning: FormGroup: Support for defaultProps will be removed from function components in a future major release. Use JavaScript default parameters instead.

The console gets crowded with many of these messages, making it hard to check actual errors or any other important debug messages.

Improvements

Migrating default props to normal JS parameters.

CC: @adamstankiewicz

[brian-smith-tcril]

We'll want to move away from using propTypes as well https://react.dev/blog/2024/04/25/react-19-upgrade-guide#removed-proptypes-and-defaultprops

[adamstankiewicz]

Thanks for flagging this, @ochavarria2u.

One important caveat we'll need to consider is how the Paragon docs site relies on propTypes and defaultProps to generate the props API sections for components (e.g., props API for Alert) as well.

[bradenmacdonald]

One important caveat we'll need to consider is how the Paragon docs site relies on propTypes and defaultProps to generate the props API sections for components (e.g., props API for Alert) as well.

We use gatsby-transformer-react-docgen which in turn uses react-docgen which has supported TypeScript since 2019. So I'm hoping it should be close to working out of the box. It's something I'm interested in exploring once #3367 has merged. With that PR, the docs site uses React 18 and is now spitting out a lot of defaultProps warnings.

[bradenmacdonald]

I'm noticing defaultProps is also causing some TypeScript bugs. For example, in the IconButtonWithTooltip component, we have correct types defined in TypeScript that make the alt prop mandatory, but through some convoluted mechanism I don't fully understand, the defaultProps are getting written with alt?: string | undefined; into dist/IconButton/index.d.ts in a way that makes typescript mark the alt prop as optional in the combined type. Commenting out its defaultProps fixes the issue.