反应：如何在输入每个字符时使密码字符可见，并在反应的几个时间间隔后隐藏（*）？答案

【问题标题】：React : How to make password characters visible when typing each character and hide(*) after few time interval in react?反应：如何在输入每个字符时使密码字符可见，并在反应的几个时间间隔后隐藏（*）？
【发布时间】：2020-04-07 11:31:12
【问题描述】：

我希望我的密码字段行为如图所示

我发现使用 jQuery 的解决方案很少，并尝试将其转换为 react，但它的行为与 react 不同，因为有一个 setState 会延迟设置值。这是我的反应代码，它的行为不一致。

    import React from "react";
    import ReactDOM from "react-dom";

// Example JS object used for CSS styling
const styles = {
  facebookBtn: {
    backgroundColor: "rgb(51, 89, 157)"
  },
  form: {
    textAlign: "center"
  }
};

export class Login extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      userName: "",
      password: "",
      passHidden: ""
    };
  }
  handleOnSubmit = e => {
    e.preventDefault();
    console.log("Submitted!");
  };

  onUserNameChange = e => {
    const value = e.target.value;
    this.setState({
      userName: value
    });
  };
  onHiddenPasswordChange = e => {};

  onPasswordChange = e => {
    const passwordValue = e.target.value;
    const hiddenPassValue = this.state.passHidden;

    let showLength = 1;
    let hideAll = setTimeout(() => {}, 0);

    let offset = passwordValue.length - hiddenPassValue.length;

    if (offset > 0) {
      this.setState({
        passHidden:
          hiddenPassValue +
          passwordValue.substring(
            hiddenPassValue.length,
            hiddenPassValue.length + offset
          )
      });
    } else if (offset < 0) {
      this.setState({
        passHidden: hiddenPassValue.substring(
          0,
          hiddenPassValue.length + offset
        )
      });
    }

    // Change the visible string
    if (passwordValue.length > showLength) {
      this.setState({
        password:
          passwordValue
            .substring(0, passwordValue.length - showLength)
            .replace(/./g, "•") +
          passwordValue.substring(
            passwordValue.length - showLength,
            passwordValue.length
          )
      });
    }

    // Set the timer
    clearTimeout(hideAll);
    hideAll = setTimeout(() => {
      this.setState({
        password: passwordValue.replace(/./g, "•")
      });
    }, 1000);
      };

      render() {
         return (
      <form style={styles.form} onSubmit={this.handleOnSubmit}>
        <h4>Welcome Back!</h4>
        <div className="form-group row">
          <input
            className="input"
            value={this.state.userName}
            onChange={this.onUserNameChange}
            type="text"
            placeholder="Email"
          />
        </div>
        <div className="form-group row">
          <input
            className="input"
            value={this.state.password}
            onChange={this.onPasswordChange}
            type="text"
            placeholder="Password"
          />
        </div>

        <div className="form-group row">
          <input
            className="input"
            value={this.state.passHidden}
            onChange={this.onHiddenPasswordChange}
            type="text"
            placeholder="Password"
          />
        </div>
        <div className="form-group row">
          <button className="btn" type="submit">
            Log In
          </button>
        </div>
      </form>
    );
      }
    }

     class Form extends React.Component {
      render() {
        const { children, title } = this.props;
        return (
      <div className="col-md-6 mx-auto">
        <header>
          <h1>{title}</h1>
        </header>
        {children}
      </div>
    );
      }
    }

    ReactDOM.render(<Form children={<Login />} />, document.getElementById("root"));

This is the solution link with jQuery

我们将不胜感激。

【问题讨论】：

标签： javascript jquery reactjs formik

【解决方案1】：

有很多方法可以做到这一点，但这里有一个：

const styles = {
  facebookBtn: {
    backgroundColor: "rgb(51, 89, 157)"
  },
  form: {
    textAlign: "center"
  }
};

class Login extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      userName: "",
      password: "",
      passHidden: ""
    };
    this.clocks = {};
  }

  handleOnSubmit = e => {
    e.preventDefault();
    console.log("Submitted!");
  };

  getLastIndexChar = string => {
    return string.slice(string.length - 1);
  };

  hideAllChars = fieldName => {
    const value = this.state[fieldName];
    let password = "";
    if (value.length) {
      password = Array(value.length).join("•") + "•";
    }
    this.setState({ [fieldName]: password });
  };

  setFieldClock = fieldName => {
    clearTimeout(this.clocks[fieldName]);
    this.clocks[fieldName] = setTimeout(
      () => this.hideAllChars(fieldName),
      1000
    );
  };

  getTypingHiddenPassword = value => {
    return Array(value.length).join("•") + this.getLastIndexChar(value);
  };

  handlePasswordChanged = (fieldName, value) => {
    this.setFieldClock(fieldName);
    const password = this.getTypingHiddenPassword(value);
    this.setState({ [fieldName]: password });
  };

  inputChange = ({ target: { name, value } }) => {
    switch (name) {
      case "password":
      case "passHidden":
        this.handlePasswordChanged(name, value);
        break;
      default:
        this.setState({ [name]: value });
        break;
    }
  };

  render() {
    return (
      <form style={styles.form} onSubmit={this.handleOnSubmit}>
        <h4>Welcome Back!</h4>
        <div className="form-group row">
          <input
            className="input"
            name="userName"
            value={this.state.userName}
            onChange={this.inputChange}
            type="text"
            placeholder="Email"
          />
        </div>
        <div className="form-group row">
          <input
            className="input"
            name="password"
            value={this.state.password}
            onChange={this.inputChange}
            type="text"
            placeholder="Password"
          />
        </div>

        <div className="form-group row">
          <input
            className="input"
            name="passHidden"
            value={this.state.passHidden}
            onChange={this.inputChange}
            type="text"
            placeholder="Password"
          />
        </div>
        <div className="form-group row">
          <button className="btn" type="submit">
            Log In
          </button>
        </div>
      </form>
    );
  }
}

class Form extends React.Component {
  render() {
    const { children, title } = this.props;
    return (
      <div className="col-md-6 mx-auto">
        <header>
          <h1>{title}</h1>
        </header>
        {children}
      </div>
    );
  }
}

ReactDOM.render(<Form children={<Login />} />, document.getElementById("root"));

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id="root"></div>

希望对大家有帮助，祝大家编码愉快！

【讨论】：

感谢您的所有努力！我期望的情况与此相反，我希望我输入字符的字段应该隐藏在类型上，但这里另一个字段是星号。最后一个字符仍然可见
刚刚意识到可能是图像让您感到困惑。我想在一秒钟后隐藏最后一个字符。
@PratikN 我仍然不能 100% 确定你想要什么，但这里有另一个版本可以给你一个好的开始。编码愉快。
再次感谢。如果有帮助，你能看到这个链接stackoverflow.com/questions/37186309/…吗？

【解决方案2】：

我发现解决方案唯一的错误是在 onChange 中设置和调用 setTimeout，因此它永远不会取消/清除实际的 setTimeout

解决办法

const styles = {
  facebookBtn: {
    backgroundColor: "rgb(51, 89, 157)"
  },
  form: {
    textAlign: "center"
  }
};

class Login extends React.Component {
  constructor(props) {
    super(props);
    this.hideAll = setTimeout(() => {}, 0);

    this.state = {
      userName: "",
      password: "",
      passHidden: ""
    };
  }
  handleOnSubmit = e => {
    e.preventDefault();
    console.log("Submitted!");
  };

  onUserNameChange = e => {
    const value = e.target.value;
    this.setState({
      userName: value
    });
  };
  onHiddenPasswordChange = e => {};

  onPasswordChange = e => {
    const passwordValue = e.target.value;
    const hiddenPassValue = this.state.passHidden;

    let showLength = 1;

    let offset = passwordValue.length - hiddenPassValue.length;

    if (offset > 0) {
      this.setState({
        passHidden:
          hiddenPassValue +
          passwordValue.substring(
            hiddenPassValue.length,
            hiddenPassValue.length + offset
          )
      });
    } else if (offset < 0) {
      this.setState({
        passHidden: hiddenPassValue.substring(
          0,
          hiddenPassValue.length + offset
        )
      });
    }

    // Change the visible string
    // if (passwordValue.length > showLength) {
    this.setState({
      password:
        passwordValue
          .substring(0, passwordValue.length - showLength)
          .replace(/./g, "•") +
        passwordValue.substring(
          passwordValue.length - showLength,
          passwordValue.length
        )
    });
    // }

    // Set the timer
    clearTimeout(this.hideAll);
    this.hideAll = setTimeout(() => {
      this.setState({
        password: passwordValue.replace(/./g, "•")
      });
    }, 1000);
  };

  render() {
    return (
      <form style={styles.form} onSubmit={this.handleOnSubmit}>
        <h4>Welcome Back!</h4>
        <div className="form-group row">
          <input
            className="input"
            value={this.state.userName}
            onChange={this.onUserNameChange}
            type="text"
            placeholder="Email"
          />
        </div>
        <div className="form-group row">
          <input
            className="input"
            value={this.state.password}
            onChange={this.onPasswordChange}
            type="text"
            placeholder="Password"
          />
        </div>

        <div className="form-group row">
          <input
            className="input"
            value={this.state.passHidden}
            onChange={this.onHiddenPasswordChange}
            type="text"
            placeholder="Password"
          />
        </div>
        <div className="form-group row">
          <button className="btn" type="submit">
            Log In
          </button>
        </div>
      </form>
    );
  }
}

class Form extends React.Component {
  render() {
    const { children, title } = this.props;
    return (
      <div className="col-md-6 mx-auto">
        <header>
          <h1>{title}</h1>
        </header>
        {children}
      </div>
    );
  }
}

ReactDOM.render(<Form children={<Login />} />, document.getElementById("root"));

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id="root"></div>

【讨论】：