在React函数中无法正确读取输入（没有JSX）

我这里的最终目标是做一些非常简单的电子邮件验证，并根据电子邮件的有效性使我的“下一步”按钮禁用或启用。我正在测试.isWorking（）函数（控制传递给按钮的disable属性的布尔值），当我使用email.length> 0进行测试时，该函数似乎可以正常工作！但是，当我将其略微更改为email.length> 4时，该功能将不起作用，并且会自动返回“ true”，从而禁用该按钮。任何帮助都将不胜感激-我完全坚持这一点，我将非常感激！

const validEmailRegex = RegExp(/^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/);

class Signup extends React.Component {

constructor() {
    super();
    this.state = {email: ""};
    this.handleSubmit = this.handleSubmit.bind(this);
}

isWorking (event) {
    //testing function here 
    const email = event.target;
    if (email.length > 4 ) {
        return false;
    }
    return true;

    //if (validEmailRegex.test(email) === true) {
    //   return false;
    //}
    //return true;
    }

handleSubmit(event) {
    event.preventDefault();

    if (!event.target.checkValidity()) {
       this.setState({ invalid: true, displayErrors: true, 
    });
       return;
    }

    const form = event.target;
    const data = new FormData(form);

    for (let name of data.keys()) {
       const input = form.elements[name];
       const parserName = input.dataset.parse;
       console.log('parser name is', parserName);
       if (parserName) {
          const parsedValue = inputParsers[parserName](data.get(name));
       data.set(name, parsedValue);
       }
     }

     this.setState({
        res: stringifyFormData(data), invalid: false, displayErrors: false, 
     });
 }

render() {
    const { res, invalid, displayErrors } = this.state;

    //pass boolean to the button for disabling or not 
    const isEnabled = this.isWorking(event);

    return (
        React.createElement("div", { className: "container" },
        React.createElement("div", { className: "row" },

            React.createElement("form", { onSubmit: this.handleSubmit, noValidate: true, className: displayErrors ? 'displayErrors' : '' },
            React.createElement("input", { className: "form-control", name: "formEmail", id: "formEmail", type: "email", placeholder: "email"}),),

            React.createElement("span", { className: "span"},
                 React.createElement("button", { className: "button1", disabled: isEnabled, type: "button"}, "next")
        ),));}}