Alex Sharp 🛠sharesecret.co

Posted on Jan 25, 2019 • Updated on Feb 21, 2020 • Originally published at ajsharp.com

🚫😩 An array of react refs

#todayilearned #react #facepalm #workjournal

Apparently you can't store React refs in an array. For some reason they get wiped out, so if you need to store a collection of refs, you have to do something like this (forgive me lord, for I hath sinned):

import React from 'react'

const collection = ["label 1", "label 2"]

class SinFactory extends React.Component {
  constructor(props) {
    super(props)
    this.ref0 = React.createRef()
    this.ref1 = React.createRef()
  }

  render() {
    return (
      <div>
        {collection.map((label, i) => {
          return <div key={label} 
            ref={this[`ref${i}`]}>{label}
          </div>
        })}
      </div>
    )
  }
}

It's truly filthy, but it works.

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Top comments (8)

Amantel • May 21 '19

I tried just now, setting this.myRef = []; and using callbacks ref={(ref) => { this.myRef[someval] = ref; return true; }} - everything worked perfectly.

Luke Ramus • Aug 19 '19

Thanks, this was helpful. If anyone else out there wants to do this with TypeScript and hooks, this worked like a charm for me:

const tentRefs = useRef<(HTMLDivElement | null)[]>([])

<div className="name-tent" key={studentId} ref={(ref) => { tentRefs.current.push(ref) }}>

sunanda3055 • Aug 11 '21

It worked for me as well. This is really cool. I have never used ref in loop and was facing issues, but with your help it rocked. Thanks!!

Pradnyanand Milind Pohare • Apr 20 '20

hello, how can i access stored values in myRef, like say what if i want to access next myRef value on currnet myRef, what should i do there? myRef.nextItem ?

Joost Kiens • Apr 22 '20 • Edited

How about using a combination of useRef and createRef?

const refs = useRef(collection.map(() => createRef())

return collection.map((x, i) => <div key={i} ref={refs.current[i]}>{x}</div>

The first rule of hooks states we can't call hooks (useRef) in a loop, but we can call createRef in a loop.

The array of refs (from createRef) will not trigger renders and stay in place between renders because it's safely stored in the .current created by useRef.

Using this way, we don't need to know how many refs we need to create upfront and it's a bit less noise (perhaps at the price of a little less clarity). Any downsides with this?

Ivelin • Jun 16 '20

I used callback refs by creating an empty array in the parent elementRefs = []; and then while iterating over the child components, I passed a function to the ref attribute ref={el => this.elementRefs[index] = el}. This way, it executes the function in the child, but it has elementRefs in its scope and add itself to the array. So at the end, you end up with an array elementRefs with all the ref elements in it.