reactjs - React-Native 错误 "undefined is not an object (evaluating ' _this2.onLoginSuccess.bind')"

Question

我正在使用react-native中的一个简单示例来登录用户。我添加了以下代码来处理该问题

onButtonPress() {
    const { email, password } = this.state;
    this.setState({ error: '', loading: true });

    firebase.auth().signInWithEmailAndPassword(email, password)
    .then(this.onLoginSuccess.bind(this))
    .catch(() => {
      firebase.auth().createUserWithEmailAndPassword(email, password)
      .then(this.onLoginSucess.bind(this))
      .catch(this.onLoginFail.bind(this));
    });
}

onLoginSuccess() {
    this.setState({
      email: '',
      password: '',
      loading: false,
      error: ''
    });
}

onLoginFail() {
    this.setState({
      error: 'Authentication Failed',
      loading: false
    });
}

但我收到错误“未定义不是对象(评估'_this2.onLoginSuccess.bind')”

我对react-native很陌生，所以请解释一下。

Answer 1

你不能像这样多次bind()。 bind() 就位通常且仅适用于匿名函数。

这样做:

constructor(props) {
    super(props);

    this.onLoginSuccess = this.onLoginSuccess.bind(this);
    this.onLoginFailed = this.onLoginFailed.bind(this);
} 

onButtonPress() {
    const { email, password } = this.state;
    this.setState({ error: '', loading: true });

    firebase.auth().signInWithEmailAndPassword(email, password)
    .then(this.onLoginSuccess)
    .catch(() => {
      firebase.auth().createUserWithEmailAndPassword(email, password)
      .then(this.onLoginSucess)
      .catch(this.onLoginFail);
    });
}

onLoginSuccess() {
    this.setState({
      email: '',
      password: '',
      loading: false,
      error: ''
    });
}

onLoginFail() {
    this.setState({
      error: 'Authentication Failed',
      loading: false
    });
}