Google Firebase，注册和登录错误提示

Question

目前正在开发一个使用谷歌firebase进行身份验证的登录和注册系统。登录和注册帐户功能正在运行。如果用户已经正确登录和注销，我已经添加了一个窗口警报。如果用户尝试使用现有的电子邮件注册，或者如果用户在尝试登录时输入无效的电子邮件或密码，我正在努力添加窗口警报。以下是我用于注册和登录的函数:我应该/必须添加哪些其他代码才能获得警报？

// signup
const signupForm = document.querySelector("#signup-form");
signupForm.addEventListener("submit", e => {
  e.preventDefault();

  // get user info
  const email = signupForm["signup-email"].value;
  const password = signupForm["signup-password"].value;

  // sign up the user
  auth.createUserWithEmailAndPassword(email, password).then(cred => {
    // close the signup modal & reset form
    const modal = document.querySelector("#modal-signup");
    M.Modal.getInstance(modal).close();
    signupForm.reset();
  });
});

// login
const loginForm = document.querySelector("#login-form");
loginForm.addEventListener("submit", e => {
  e.preventDefault();

  // get user info
  const email = loginForm["login-email"].value;
  const password = loginForm["login-password"].value;

  // log the user in
  auth.signInWithEmailAndPassword(email, password).then(cred => {
    // close the signup modal & reset form
    const modal = document.querySelector("#modal-login");
    M.Modal.getInstance(modal).close();
    loginForm.reset();
  });
});

Answer 1

使用then() catch()检查错误回调

firebase有一个通用错误代码列表，请在此处查看更多信息：https://firebase.google.com/docs/auth/admin/errors

示例

auth.signInWithEmailAndPassword(email, password).then(cred => {
  // close the signup modal & reset form
  const modal = document.querySelector("#modal-login");
  M.Modal.getInstance(modal).close();
  loginForm.reset();
}).then(() => {
  // do something
}).catch((error) => {
  if (error.code === 'auth/email-already-in-use') {
     alert('email already in use!');
  } else if (error.code === 'auth/network-request-failed') {
      alert('without network connection!');
  } else if (error.code === 'auth/invalid-email') {
      alert('invalid E-mail!');
      // email wrong format
  }
});