React Native setState with callback

Stars.jsx

const URL = 'https://api.github.com/repos/facebook/react-native'

class Stars extends Component {
  state : {
    stars: number
  } = {
    stars: 0
  }

  async componentDidMount() {
    await this.fetchData().done();
    // do something
  }

  async fetchData(): Promise<void> {
    const response = await fetch(URL)
    const json = await response.json()
    const stars : number = json.stargazers_count
    this.setState({stars: stars}, () => {
      // do something after the stars are rendered
    })
  }

  render() {
    return (
      <View style={styles.container}>
        <Text style={styles.text}>
          React Native has {this.state.stars} stars
        </Text>
      </View>
    )
  }
}