React特征Form 单向数据流示例详解

import * as React from 'react';
const Useremail = props => <input type="email" {...props} />
const Userpassword = props => <input type="password" {...props} />
const SubmitButton = props => <button type="submit" {...props} />
const LoginForm = () => {
  // LoginForm状态变化 => Useremail/Userpassword组件
  const [email, setEmail] = React.useState('');
  const [password, setPassword] = React.useState('');
  const handleEmail = (e) => {
    setEmail(e.target.value);
  };
  const handlePassword = (e) => {
    setPassword(e.target.value);
  };
  const handleSubmit = (e) => {
    e.preventDefault();
    alert(email + ' ' + password);
  };
  return (
    <form onSubmit={handleSubmit}>
      <div>
        <label htmlFor="email">Email</label>
        <Useremail
          id="email"
          type="text"
          value={email}
          onChange={handleEmail}
        />
      </div>
      <div>
        <label htmlFor="password">Password</label>
        <Userpassword
          id="password"
          type="password"
          value={password}
          onChange={handlePassword}
        />
      </div>
      <SubmitButton type="submit">Submit</SubmitButton>
    </form>
  );
};
export { LoginForm };

import * as React from 'react';
// Useremail/Userpassword组件状态变化 => LoginForm父组件
const Useremail = ({updateUseremail, ...props}) =>
  <input type="email" 
         onChange={e => updateUseremail(e.target.value)}
         {...props} />
const Userpassword = ({updateUserpassword, ...props}) => 
  <input type="password" 
         onChange={e => updateUserpassword(e.target.value)}
         {...props} />
const SubmitButton = props => <button type="submit" {...props} />
const LoginForm = () => {
  // LoginForm状态变化 => Useremail/Userpassword组件
  const [email, setEmail] = React.useState('');
  const [password, setPassword] = React.useState('');
  const handleSubmit = (e) => {
    e.preventDefault();
    alert(email + ' ' + password);
  };
  return (
    <form onSubmit={handleSubmit}>
      <div>
        <label htmlFor="email">Email</label>
        <Useremail
          id="email"
          type="text"
          value={email}
          updateUseremail={setEmail}
        />
      </div>
      <div>
        <label htmlFor="password">Password</label>
        <Userpassword
          id="password"
          type="password"
          value={password}
          updateUserpassword={setPassword}
        />
      </div>
      <SubmitButton type="submit">Submit</SubmitButton>
    </form>
  );
};
export { LoginForm };