this.refs.something returns "undefined"

JavascriptReactjsReact DomReact Ref

Javascript Problem Overview


I have an element with a ref that is defined and ends up getting rendered into the page :

    <div ref="russian" ...>
       ...
    </div>

I want to access the DOM element properties like offset... or something. However, I keep getting undefined and I haven't the faintest idea why. After some searching it's clear that refs are only applicable to one file but I'm not using this anywhere besides this one page. I'm saying this to log it:

console.log('REFS', this.refs.russian);

What could be causing this?

Javascript Solutions


Solution 1 - Javascript

Check that you are not accessing ref before the child component has been mounted. E.g. it doesn't work in componentWillMount. A different pattern which auto invokes ref related callback after the element has been mounted is this-

<div ref={(elem)=>(console.log(elem))}/>

You can use this notation to get mounted elements in deep nesting as well -

<div ref={this.props.onMounted}/>

Solution 2 - Javascript

The correct place to work with refs is inside specific React lifecycle methods e.g. ComponentDidMount, ComponentDidUpdate

You cannot reference refs from the render() method. Read more about the cautions of working with refs here.

If you move your console.log('REFS', this.refs.russian); call to ComponentDidMount or ComponentDidUpdate lifecycle methods (assuming you are on React >= 14) you should not get undefined as a result.

UPDATE: also refs will not work on stateless components per the caution link above

Solution 3 - Javascript

Update since React version 16.4

In your constructor method define your ref like this

constructor(props) {
  super(props);
  this.russian = React.createRef();
}

In your render where you are using ref do this.

<input
  name="russian"
  ref={this.russian} // Proper way to assign ref in react ver 16.4
/>  

For e.g if you want to have focus when component mounts do this

componentDidMount() {
  console.log(this.russian); 
  this.russian.current.focus();
 }

Reference Refs Documentation React

Solution 4 - Javascript

I was having a similar issue in my form validation methods, trying to assign this.ref.current.reportValidity()

Writing the method I was doing this in as validate = () => {} instead of validate() {} helped me out, but I'm not totally sure why exactly, just something I remembered from habits I had in my past work experience that gave me this. Hope it helps and could someone kindly clarify this answer with why this might work exactly.

Solution 5 - Javascript

If you are exporting class withStyle, please remove and export default nomally.

Solution 6 - Javascript

Instead of putting your Console.log inside the function example(){...} you should put it inside:

example=()=>{....}

Attributions

All content for this solution is sourced from the original question on Stackoverflow.

The content on this page is licensed under the Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) license.

Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionJohn DoeView Question on Stackoverflow
Solution 1 - JavascripthazardousView Answer on Stackoverflow
Solution 2 - JavascriptjurassixView Answer on Stackoverflow
Solution 3 - JavascriptAdeel ImranView Answer on Stackoverflow
Solution 4 - JavascriptStatikView Answer on Stackoverflow
Solution 5 - Javascriptvũ việt hoàng vũView Answer on Stackoverflow
Solution 6 - JavascriptMaykelView Answer on Stackoverflow