React:使用keydown调用函数(ctrl + enter)

Question

我正在创建一个应用程序,当用户按下ctrl + enter时,我想启动一个函数(在本例中为showMessage).我怎么做,最好没有jQuery.

import React from "react"

const App = React.createClass({
  showMessage () {
    console.log('hit');
  },
  render () {
    return (
      <div>
        <button onClick={this.showMessage}>Hit</button>
      </div>
    );
  }
});


module.exports = App;

Answer 1

1. 添加事件监听器: document.addEventListener('keydown',this.keydownHandler)

2. 然后在处理程序检查 e.keyCode===13 && e.ctrlKey

3. 不要忘记删除事件监听器 componentWillUnmount

const App = React.createClass({
  showMessage () {
    alert('SOME MESSAGE');
  },
  keydownHandler(e){
    if(e.keyCode===13 && e.ctrlKey) this.showMessage()
  },
  componentDidMount(){
    document.addEventListener('keydown',this.keydownHandler);
  },
  componentWillUnmount(){
    document.removeEventListener('keydown',this.keydownHandler);
  },
  render () {
    return (
      <div>
        <h1>Press Ctrl+Enter</h1>
        <button onClick={this.showMessage}>Hit</button>
      </div>`
    );
  }
});
export default App;

Answer 2

也可以使用功能组件来完成

export function App() {
  const showMessage = () => {
    alert('SOME MESSAGE');
  };
  const keydownHandler = (e) => {
    if(e.key === 'Enter' && e.ctrlKey) showMessage()
  };
  React.useEffect(() => {
    document.addEventListener('keydown', keydownHandler);
    return () => {
      document.removeEventListener('keydown', keydownHandler);
    }
  }, []);

  return (
    <div>
      <h1>Press Ctrl+Enter</h1>
      <button onClick={showMessage}>Hit</button>
    </div>
  );
}