text: export default class Passport {
      constructor() {
          this.isLogin = false;
      }
      
      login(username, password, callback) {
          if (username === 'admin' && password === 'uwaadmin') {
              // login successfully
              this.isLogin = true;
              // send the operation to the caller after login
              callback();
          } else {
              // failed
              // pop a message
              alert('Login failed!');
          }
      }
  
      storageLogin(username, password) {
          if (username === 'admin' && password === 'uwaadmin') {
              // login successfully
              // send the operation to the caller after login
              return true;
          } else {
              // failed
              // pop a message
              return false;
          }
      }
  }