Minor flow issue in 3.1.0 update

[vikalp-sajwan]

First and foremost, thanks to all the people who are involved in this awesome project.

Are you reporting a bug or runtime error?

Setup up issue.
This is a flow error issue when using Async Select component. This was introduced in #3690 with changes in isLoading prop.
Can't reproduce in sandbox as this is related to setup.

Reproduction steps

• clone https://github.com/vikalp-sajwan/react-select
• run yarn flow check

The reproduction code is just the fork of this repository with a single component file using the Async Select.
https://github.com/vikalp-sajwan/react-select/blob/master/packages/react-select/src/Async-flow-test-component.js

Issue

➜  react-select git:(flow-issue) ✗ yarn flow check
yarn run v1.22.4
$ /home/code/react-select/node_modules/.bin/flow check
Error ┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈ packages/react-select/src/Async-flow-test-component.js:38:10

Cannot create AsyncSelect element because undefined [1] is incompatible with boolean [2] in property isLoading.

     packages/react-select/src/Async-flow-test-component.js
      35│     return (
      36│       <div>
      37│         <pre>inputValue: "{this.state.inputValue}"</pre>
      38│         <AsyncSelect
      39│           cacheOptions
      40│           loadOptions={loadOptions}
      41│           defaultOptions
      42│           onInputChange={() => this.handleInputChange('green')}
      43│           isLoading
      44│         />
      45│       </div>
      46│     );
      47│   }

     packages/react-select/src/Async.js
 [2]  34│   isLoading: boolean,

     packages/react-select/src/Select.js
 [1] 160│   isLoading: boolean,



Found 1 error

Issue Cause

Not sure, but seems the defaultProps value defined in Select.js is making it interpret as optional prop, which in turn means it could be undefined, causing the issue.

Possible Solution

Making the isLoading prop optional is fixing the issue.

Are you making a feature request?

No

[ebonow]

Greetings @vikalp-sajwan,

To avoid confusion I have removed my prior comments as I mistook the implementation at a quick first glance as object props and not JSX props. I will reopen to further investigate.

[ebonow]

@Methuselah96 can you confirm if this is still an issue or not. I tested this in master and wasn't able to replicate. It seems you had been discussing this issue in another thread so wanted to verify.

[Methuselah96]

Yeah, not sure, but the Flow types should no longer be relevant with the conversion to TypeScript (#4489).