react-native-line-style

npm i react-native-line-style --save

  import {setSize} from 'react-native-line-style'
  
  setSize(750)
  
  AppRegistry.registerComponent(appName, () => App);

  import y from 'react-native-line-style'

  <View style={[y.h(100), y.ba(1), y.bdColor('#000')]}>
    <Text style={[y.fSize(14), y.color('#333')]}>hello,world</Text>
  </View>