DefinitelyTyped/types/react-native-qrcode/react-native-qrcode-tests.tsx

import * as React from 'react';
import QRCode from 'react-native-qrcode';

import {
  AppRegistry,
  StyleSheet,
  View,
  TextInput
} from 'react-native';

class HelloWorld extends React.Component {
  state = {
    text: 'http://facebook.github.io/react-native/',
  };

  render() {
    return (
      <View style={styles.container}>
        <TextInput
          style={styles.input}
          onChangeText={(text) => this.setState({ text })}
          value={this.state.text}
        />
        <QRCode
          value={this.state.text}
          size={200}
          bgColor='purple'
          fgColor='white' />
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: 'white',
    alignItems: 'center',
    justifyContent: 'center'
  },

  input: {
    height: 40,
    borderColor: 'gray',
    borderWidth: 1,
    margin: 10,
    borderRadius: 5,
    padding: 5,
  }
});