onKeyDown event not working on divs in React

Question

I want to use a keyDown event on a div in React. I do:

  componentWillMount() {
      document.addEventListener(\"keydown\", this.onKeyPressed.bind(this));
          


        

Answer 1

You need to write it this way

<div 
    className="player"
    style={{ position: "absolute" }}
    onKeyDown={this.onKeyPressed}
    tabIndex="0"
  >

If onKeyPressed is not bound to this, then try to rewrite it using arrow function or bind it in the component constructor.

Answer 2

You're missing the binding of the method in the constructor. This is how React suggests that you do it:

class Whatever {
  constructor() {
    super();
    this.onKeyPressed = this.onKeyPressed.bind(this);
  }

  onKeyPressed(e) {
    // your code ...
  }

  render() {
    return (<div onKeyDown={this.onKeyPressed} />);
  }
}

There are other ways of doing this, but this will be the most efficient at runtime.

Answer 3

You have to prevent default event from triggering.

onKeyPressed(e) {
   e.preventDefault();
   console.log(e.key);
}

Answer 4

Using the div trick with tab_index="0" or tabIndex="-1" works, but any time the user is focusing a view that's not an element, you get an ugly focus-outline on the entire website. This can be fixed by setting the CSS for the div to use outline: none in the focus.

Here's the implementation with styled components:

import styled from "styled-components"

const KeyReceiver = styled.div`
  &:focus {
    outline: none;
  }
`

and in the App class:

  render() {
    return (      
      <KeyReceiver onKeyDown={this.handleKeyPress} tabIndex={-1}>
          Display stuff...
      </KeyReceiver>
    )

Answer 5

You're thinking too much in pure Javascript. Get rid of your listeners on those React lifecycle methods and use event.key instead of event.keyCode (because this is not a JS event object, it is a React SyntheticEvent). Your entire component could be as simple as this (assuming you haven't bound your methods in a constructor).

onKeyPressed(e) {
  console.log(e.key);
}

render() {
  let player = this.props.boards.dungeons[this.props.boards.currentBoard].player;
  return (
    <div 
      className="player"
      style={{ position: "absolute" }}
      onKeyDown={this.onKeyPressed}
    >
      <div className="light-circle">
        <div className="image-wrapper">
          <img src={IMG_URL+player.img} />
        </div>
      </div>
    </div>
  )
}

Answer 6

You should use tabIndex attribute to be able to listen onKeyDown event on a div in React. Setting tabIndex="0" should fire your handler.