React Native Stream Group Chat Tutorial: Login code

login code in Login.js

// src/screens/Login.js
login = async () => {
  const username = this.state.username;
  this.setState({
    is_loading: true
  });

  if (username) {
    try {
      const user_id = StringHash(username).toString();
      const response = await axios.post(`${CHAT_SERVER}/auth`, {
        user_id
      });
      
      this.props.navigation.navigate("Chat", {
        user_id,
        username,
        user_token: response.data.token
      });

    } catch (err) {
      console.log("error: ", err);
    }
  }    
}