Eslint-plugin-react: `no-unused-prop-types` doesn't check `nextProps` of `componentWillReceiveProps`

[bywo]

If a prop is only used in the context of nextProps, the lint rule mistakenly thinks that the prop is never used.

Here's a repro case:

import React, {PropTypes} from "react";

export default React.createClass({

  propTypes: {
    foo: PropTypes.bool, // this line gets flagged when it shouldn't
    bar: PropTypes.func,
  },

  componentWillReceiveProps (nextProps) {
    if (nextProps.foo) {
      return;
    }
  },

  render () {
    this.props.bar;
    return <div />;
  }
});

[ljharb]

What's the use case for a prop that's not used in the render path?

[bywo]

It might not be idiomatic React, but in this case, we're waiting on a prop
to turn true and when it does, we trigger a route change. You could
imagine a signup form component waiting for nextProps.signupCompleted to
be true, and then redirecting to the homepage.

On Wed, Aug 31, 2016 at 10:07 PM Jordan Harband [email protected]
wrote:

What's the use case for a prop that's not used in the render path?

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[EvHaus]

This will be fixed by https://github.com/yannickcr/eslint-plugin-react/pull/792

[bywo]

Great! Thanks @EvNaverniouk

[mjilugu]

Hi, I still get this same error. When we use a prop only with nextProps to set the state in the componentWillRecieveProps(nextProps) method and not elsewhere we get react/no-used-prop-types error for the prop in the propTypes block.

[wx2228]

still getting this error too.

[jseminck]

This should be fixed. @wx2228. what version of eslint-plugin-react do you use? If using the latest, could you provide sample code of what is failing? Then I can look into it. Thanks!

[wx2228]

@jseminck thanks for the prompt reply. I am using 6.10.3. I will upgrade it

[andfelzapata]

it also wont check nextProps if componentWillReceiveProps is declared as an arrow function.

[ljharb]

@andfelzapata would you file that as a separate issue?