30秒学会 React 片段 – Toggle

Renders a toggle component.

• Use the React.useState() to initialize the isToggleOn state variable to false.
• Use an object, style, to hold the styles for individual components and their states.
• Return a <button> that alters the component’s isToggledOn when its onClick event is fired and determine the appearance of the content based on isToggleOn, applying the appropriate CSS rules from the style object.

代码实现

function Toggle(props) {
  const [isToggleOn, setIsToggleOn] = React.useState(false);
  style = {
    on: {
      backgroundColor: 'green'
    },
    off: {
      backgroundColor: 'grey'
    }
  };

  return (
    <button onClick={() => setIsToggleOn(!isToggleOn)} style={isToggleOn ? style.on : style.off}>
      {isToggleOn ? 'ON' : 'OFF'}
    </button>
  );
}

使用样例

ReactDOM.render(<Toggle />, document.getElementById('root'));