React 动态填加class，使用classnames库代码-CFANZ编程社区

React 动态填加class，使用classnames库代码_html

使用classnames：

一个简单的JavaScript实用程序，用于有条件地将类名连接在一起。

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <title>React 动态填加class</title>
    <script src="https://unpkg.com/react@16/umd/react.development.js"></script>
    <script src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
    <script src="https://unpkg.com/babel-standalone@6.15.0/babel.min.js"></script>
    <script src="https://cdn.bootcss.com/classnames/2.2.5/index.js"></script>
    <style type="text/css">
      .m-test{width: 100px;height: 100px;background-color: red;}
      .m-test.active{background-color: blue;}
    </style>
  </head>
  <body>
    <div id="root"></div>
    <script type="text/babel">
      class Toggle extends React.Component {
        constructor(props) {
          super(props);
          this.state = {
            isToggleOn: true,
            active: true
          };
 
          // 这个绑定是必要的，使`this`在回调中起作用
          this.handleClick = this.handleClick.bind(this);
        }
 
        handleClick() {
          this.setState(prevState => ({
            isToggleOn: !prevState.isToggleOn,
            active: !prevState.isToggleOn
          }));
        }
 
        render() {
          let testClass = classNames({
            "m-test": true,
            active: this.state.active
          });
          return (
            <div>
              <button onClick={this.handleClick}>
                {this.state.isToggleOn ? 'ON' : 'OFF'}
              </button>
              <div className={testClass}></div>
            </div>
          );
        }
      }
 
      ReactDOM.render(
        <Toggle />,
        document.getElementById('root')
      );
    </script>
  </body>
</html>

原生写法：

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <title>React 动态填加class</title>
    <script src="https://unpkg.com/react@16/umd/react.development.js"></script>
    <script src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
    <script src="https://unpkg.com/babel-standalone@6.15.0/babel.min.js"></script>
    <style type="text/css">
      .m-test{width: 100px;height: 100px;background-color: red;}
      .m-test.active{background-color: blue;}
    </style>
  </head>
  <body>
    <div id="root"></div>
    <script type="text/babel">
      class Toggle extends React.Component {
        constructor(props) {
          super(props);
          this.state = {
            isToggleOn: true
          };
 
          // 这个绑定是必要的，使`this`在回调中起作用
          this.handleClick = this.handleClick.bind(this);
        }
 
        handleClick() {
          this.setState(prevState => ({
            isToggleOn: !prevState.isToggleOn
          }));
        }
 
        render() {
          return (
            <div>
              <button onClick={this.handleClick}>
                {this.state.isToggleOn ? 'ON' : 'OFF'}
              </button>
              <div className={"m-test " + (this.state.isToggleOn ? 'active' : '')}></div>
            </div>
          );
        }
      }
 
      ReactDOM.render(
        <Toggle />,
        document.getElementById('root')
      );
    </script>
  </body>
</html>

ES6写法，在chrome里调试时会影响js代码，不推荐。

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <title>React 动态填加class</title>
    <script src="https://unpkg.com/react@16/umd/react.development.js"></script>
    <script src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
    <script src="https://unpkg.com/babel-standalone@6.15.0/babel.min.js"></script>
    <style type="text/css">
      .m-test{width: 100px;height: 100px;background-color: red;}
      .m-test.active{background-color: blue;}
    </style>
  </head>
  <body>
    <div id="root"></div>
    <script type="text/babel">
      class Toggle extends React.Component {
        constructor(props) {
          super(props);
          this.state = {
            isToggleOn: true
          };
 
          // 这个绑定是必要的，使`this`在回调中起作用
          this.handleClick = this.handleClick.bind(this);
        }
 
        handleClick() {
          this.setState(prevState => ({
            isToggleOn: !prevState.isToggleOn
          }));
        }
 
        render() {
          return (
            <div>
              <button onClick={this.handleClick}>
                {this.state.isToggleOn ? 'ON' : 'OFF'}
              </button>
              <div className={`m-test ${this.state.isToggleOn ? 'active' : ''}`}></div>
            </div>
          );
        }
      }
 
      ReactDOM.render(
        <Toggle />,
        document.getElementById('root')
      );
    </script>
  </body>
</html>