JS 当中的函数柯里化和高阶函数

function sum(a, b, c) {
  return a + b + c;
}
sum(1, 2, 3); // 6

function sum(a) {
  return (b) => {
    return (c) => {
      return a + b + c;
    };
  };
}

sum(1)(2)(3); // 6

class Login extends React.Component {
  //初始化状态
  state = {
    username: "", //用户名
    password: "", //密码
  };

  //保存表单数据到状态中
  saveFormData = (dataType) => {
    return (event) => {
      this.setState({ [dataType]: event.target.value });
    };
  };

  //表单提交的回调
  handleSubmit = (event) => {
    event.preventDefault(); //阻止表单提交
    const { username, password } = this.state;
    alert(`你输入的用户名是：${username},你输入的密码是：${password}`);
  };
  render() {
    return (
      <form onSubmit={this.handleSubmit}>
        用户名：
        <input
          onChange={this.saveFormData("username")}
          type="text"
          name="username"
        />
        密码：
        <input
          onChange={this.saveFormData("password")}
          type="password"
          name="password"
        />
        <button>登录</button>
      </form>
    );
  }
}