forwardRef trips up docgen

[jonathanloske]

Describe the bug
When implementing a Component in the way described below, the Storybook Props block (created via react-docgen-typescript-loader) only shows the following text:

"Cannot read property 'appearance' of undefined"

To Reproduce
Declare a component in way mentioned under "Code snippets".

Expected behavior
The Props block should display the corresponding Props.

Screenshots

Code snippets
Button.tsx

type ButtonProps = {
  appearance?: "primary" | "secondary" | "ghost";
} & JSX.IntrinsicElements["button"];

const Button: RefForwardingComponent<HTMLButtonElement, ButtonProps> = React.forwardRef(({ appearance, ...otherProps}, ref) => (
  <button>...</button>
))

Button.displayName = "Button";

Button.defaultProps = {
  appearance: "primary"
};

Button.stories.tsx

import React from "react";
import { storiesOf } from "@storybook/react";
import { Button } from "./Button";

storiesOf("Button", module)
  .addParameters({
    component: Button
  })
  .add("primary", () => (
    <Button appearance="primary">
      My primary button!
    </Button>
  ))
;

System:

package.json

"react-docgen-typescript-loader": "^3.3.0"

Update: Also tested with 3.6.0.

Tried out with both Storybook 5.2.5 and Storybook 5.3.0-beta.1

Using stories in the TSX file format but encountered the error also when using the JSX file format.

Component is in TSX format.

Please paste the results of npx -p @storybook/cli@next sb info here.

  System:
    OS: macOS 10.15.1
    CPU: (4) x64 Intel(R) Core(TM) i7-7567U CPU @ 3.50GHz
  Binaries:
    Node: 10.16.0 - ~/.nvm/versions/node/v10.16.0/bin/node
    npm: 6.9.0 - ~/.nvm/versions/node/v10.16.0/bin/npm
  Browsers:
    Chrome: 78.0.3904.97
    Safari: 13.0.3
  npmPackages:
    @storybook/cli: ^5.3.0-beta.1 => 5.3.0-beta.1

Additional context
Used to work before introducing RefForwardingComponent and React.forwardRef

[jonathanloske]

Mirror issue on Storybook side: storybookjs/storybook#8881

[jonathanloske]

Relevant issue in react-docgen: reactjs/react-docgen#267

[jonathanloske]

This might be fixed with react-docgen 5.0.0-beta.1 which includes a pull request that is titled "Fully support forwardRef": reactjs/react-docgen#350

[awinograd]

@jonathanherdt i ran into this issue as well. I dont think the react-docgen issue is related since this loader uses something else under the hood.

I was able to get the docgenInfo object to show up by destructuring forwardRef and use it directly. e.g.

// bad
import React from 'react';
export const MyComponent = React.forwardRef<A, B>( ... )
// good
import React, { forwardRef } from 'react';
export const MyComponent = forwardRef<A, B>( ... )
`

[jeffcstock]

This is not working for me, event with destructuring. Getting the cannot read property ... of undefined.

I'm on version 5.2.8.

Can confirm that taking the forwardRef out displays all props correctly.

import React, { ElementType, forwardRef, Ref, ReactElement } from 'react'

export const Button = forwardRef(
  (props: ButtonProps, ref: Ref<HTMLAnchorElement>) => {
   ...
  }
)

[awinograd]

@jeffcstock have you tried parameterizing your forwardRef invocation?

i.e. forwardRef<HTMLAnchorElement, ButtonProps>((props, ref) => { ... })

[jeffcstock]

@awinograd thanks for your response, but yes I can confirm that doesn't help things. Same exact result. 😕

[awinograd]

@jeffcstock no problem. sorry i wasn't more help!

[jonathanloske]

@jeffcstock Storybook 5.3 was just released and fixes this for me. Maybe give it a shot?

[jeffcstock]

That fixed it, thank you @jonathanherdt!

[strothj]

Closing this issue because of multiple reports that it's been resolved. Leave a message if it's still a problem.