[flow-strict] Flow strict in Picker.js, PickerIOS.ios.js, PickerAndroid.android.js

[nissy-dev]

Related to #22100

Turn Flow strict mode on for Picker

Test Plan:

• npm run prettier
• npm run flow-check-ios
• npm run flow-check-android

[pull-bot]

	Warnings
⚠️	📋 Release Notes - This PR may have incorrectly formatted Release Notes.

Generated by 🚫 dangerJS

[elicwhite]

We typically prefer $ReadOnlyArray over Array. Hopefully the code in this file isn't modifying this directly so having it be a read only array should be fine with Flow.

[nissy-dev]

👍

[nissy-dev]

I think this fix is not needed.
But flow needs... is this correct?

[elicwhite]

I'm not sure without trying to test it out myself. What flow error do you get without this change?

[nissy-dev]

I get this error...

Cannot create Picker element because string [1] is incompatible with number [2] in the
first argument of property onValueChange.

     RNTester/js/PermissionsExampleAndroid.android.js
     38│     return (
     39│       <View style={styles.container}>
     40│         <Text style={styles.text}>Permission Name:</Text>
     41│         <Picker
     42│           style={styles.picker}
     43│           selectedValue={this.state.permission}
                    // this line causes error
     44│           onValueChange={this._onSelectPermission.bind(this)}>
     45│           <Item
     46│             label={PermissionsAndroid.PERMISSIONS.CAMERA}
     47│             value={PermissionsAndroid.PERMISSIONS.CAMERA}
     48│           />
     49│           <Item
     50│             label={PermissionsAndroid.PERMISSIONS.READ_CALENDAR}
     51│             value={PermissionsAndroid.PERMISSIONS.READ_CALENDAR}
     52│           />
     53│           <Item
     54│             label={PermissionsAndroid.PERMISSIONS.ACCESS_FINE_LOCATION}
     55│             value={PermissionsAndroid.PERMISSIONS.ACCESS_FINE_LOCATION}
     56│           />
     57│         </Picker>
     58│         <TouchableWithoutFeedback onPress={this._checkPermission}>
     59│           <View>
     60│             <Text style={[styles.touchable, styles.text]}>
       :
 [1] 79│   _onSelectPermission = (permission: string) => {

[nissy-dev]

I think this fix is not needed.
But flow needs... is this correct?

[nissy-dev]

I get this error....

Cannot create Picker element because string [1] is incompatible with number [2] in the
first argument of property onValueChange.

     RNTester/js/PickerExample.js
      37│     return (
      38│       <RNTesterPage title="<Picker>">
      39│         <RNTesterBlock title="Basic Picker">
      40│           <Picker
      41│             style={styles.picker}
      42│             selectedValue={this.state.selected1}
                      // this line causes error
      43│             onValueChange={this.onValueChange.bind(this, 'selected1')}>
      44│             <Item label="hello" value="key0" />
      45│             <Item label="world" value="key1" />
      46│           </Picker>
      47│         </RNTesterBlock>
      48│         <RNTesterBlock title="Disabled picker">
      49│           <Picker
        :
 [1] 119│   onValueChange = (key: string, value: string) => {

     Libraries/Components/Picker/Picker.js
 [2]  73│   onValueChange?: ?(itemValue: string | number, itemIndex: number) => mixed,

[turnrye]

Hi @nd-02110114 , is this part of the larger effort under #22100? I plan to combine those entries in the changelog to a single entry, so the changelog section in this PR is n/a. I'll make sure that once this PR lands, you're attributed for your contribution.

[elicwhite]

Ah, this makes sense to me. Since an item can have a value of a string or number the function handling the value change must deal with strings or numbers.

[facebook-github-bot]

@TheSavior is landing this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[facebook-github-bot]

I tried to merge this pull request into the Facebook internal repo but some checks failed. To unblock yourself please check the following: Does this pull request pass all open source tests on GitHub? If not please fix those. Does the code still apply cleanly on top of GitHub master? If not can please rebase. In all other cases this means some internal test failed, for example a part of a fb app won't work with this pull request. I've added the Import Failed label to this pull request so it is easy for someone at fb to find the pull request and check what failed. If you don't see anyone comment in a few days feel free to comment mentioning one of the core contributors to the project so they get a notification.

[react-native-bot]

@nd-02110114 merged commit 23845fb into facebook:master.