fix exception when ES6 class with no propTypes defined before calling requireNativeComponent

[kejinlu]

No description provided.

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[ide]

I have a question - what kind of native view does not have custom props? All the native views so far have special props to customize them.

[sahrens]

Please use === or !== instead of their looser counterparts whenever possible.

[sahrens]

Or just check truthiness without comparing to undefined.

[vjeux]

Can you provide more context in how you experienced this error?

[kejinlu]

React Native "Native UI Components (iOS)" Guide

call requireNativeComponent before propTypes ，Then will experience this error

// MapView.js
var React = require('react-native');
var { requireNativeComponent } = React;
class MapView extends React.Component {
render() {
return <RCTMap {...this.props} />;
}
}
var RCTMap = requireNativeComponent('RCTMap', MapView);
MapView.propTypes = {
/**
* When this property is set to `true` and a valid camera is associated
* with the map, the camera’s pitch angle is used to tilt the plane
* of the map. When this property is set to `false`, the camera’s pitch
* angle is ignored and the map is always displayed as if the user
* is looking straight down onto it.
*/
pitchEnabled: React.PropTypes.bool,
};
module.exports = MapView;

[ide]

I think there's a bug in that code, since pitchEnabled will not get verified (docs fix at #1271). However it's also bad to get a confusing error about undefined not being an object, so I think we should change verifyPropTypes to assert that component.propTypes is defined and throw a helpful error message when it's missing.

[sahrens]

@ide is right - maybe change this PR to throw a more useful error?

[kejinlu]

Should I close the request?

[ide]

@kejinlu can you update this PR so that it asserts?

[kejinlu]

@ide@sahrens I found another problem ,the "component.displayName" in the verifyPropTypes code always be undefined. Should set component.displayName with some value manually in the previous context?Or just use "component.name"

[sahrens]

"component.displayName" in the verifyPropTypes code always be undefined

Looks like for ES6 classes name works, but for React.createClassdisplayName works.

@spicyj : any idea why this is inconsistent? Is there a better mechanism than just checking both like

'' + (component.name || component.displayName) + ' has no propTypes defined`'

[sahrens]

import

[sahrens]

Can you figure out the right way to include the component name in the error messages and make it consistent in the function?

[sahrens]

@facebook-github-bot import

[facebook-github-bot]

Thanks for importing. If you are an FB employee go to https://our.intern.facebook.com/intern/opensource/github/pull_request/966263836738882/int_phab to review.

[sophiebits]

displayName || name is the right way to do it.