PropTypes not working

[marvinhagemeister]

Do you want to request a feature or report a bug?
Bug

What is the current behaviour?
PropType functions are never called

If the current behaviour is a bug, please provide the steps to reproduce.

Using the default preact-cli template:

import { h, Component } from 'preact';
import PropTypes from 'prop-types';

class Foo extends Component {
  static propTypes = {
	// Will never be called :/
    foo: PropTypes.string.isRequired
  }

  render() {
    return <h1>foo {this.props.foo}</h1>;
  }
}

export default class App extends Component {
	render() {
		return <div><Foo /></div>
	}
}

What is the expected behaviour?

Prop-Type validation should be called.

If this is a feature request, what is motivation or use case for changing the behaviour?

Please mention other relevant information.

• Node version 10.0.9
• npm version 6.0.0
• Operating system MacOSX
• CLI version: 2.2.1
• Browser Chrome/Firefox

[lukeed]

Is this in a production build? They are removed during build and kept within watch:

https://github.com/developit/preact-cli/blob/master/src/lib/babel-config.js#L28

[marvinhagemeister]

@lukeed This issue occurs in development mode. The statements and prop-types library are included in the generated bundle, but the code for prop-types is never executed.

Digging deeper it seems like preact-compat should trigger the prop type checking. But even then when I use the Component export from there, the validation for prop-types is never run.

[ForsakenHarmony]

have you tried importing "react"?

[marvinhagemeister]

@ForsakenHarmony yep, switching to the react import doesn't help although the webpack config points to it being aliased to preact-compat.

Stepping through with a debugger it looks like the Component class is still used directly from preact instead of preact-compat. Therefore createClass which sets up the prop-type handling is never called. The only thing that's called from compat is the options.vnode hook.

[marvinhagemeister]

Turns out that this is an issue with our process.env.NODE_ENV check in preact-compat. Made a PR there preactjs/preact-compat#504 .

Closing the issue here because it is not an issue with preact-cli itself.