An implementation of https://css-tricks.com/the-cleanest-trick-for-autogrowing-textareas/ in React

AutoGrowingTextArea.js

// An implementation of https://css-tricks.com/the-cleanest-trick-for-autogrowing-textareas/ in React

import React, { useRef } from 'react'

const AutoGrowingTextArea = props => {
  const grower = useRef(null);

  return(
    <div className="AutoGrowingTextArea" ref={grower}>
      <textarea 
        name={props.name} 
        id={props.id} 
        onInput={ (e) => grower.current.dataset.replicatedValue = e.target.value }></textarea>
    </div>
  )
}

AutoGrowingTextArea.defaultProps = {
  name: 'text',
  id: 'text'
}

export default AutoGrowingTextArea

AutoGrowingTextArea.scss

.AutoGrowingTextArea {
  /* easy way to plop the elements on top of each other and have them both sized based on the tallest one's height */
  display: grid;
}
.AutoGrowingTextArea::after {
  /* Note the weird space! Needed to preventy jumpy behavior */
  content: attr(data-replicated-value) " ";

  /* This is how textarea text behaves */
  white-space: pre-wrap;

  /* Hidden from view, clicks, and screen readers */
  visibility: hidden;
}
.AutoGrowingTextArea > textarea {
  /* You could leave this, but after a user resizes, then it ruins the auto sizing */
  resize: none;

  /* Firefox shows scrollbar on growth, you can hide like this. */
  overflow: hidden;
}
.AutoGrowingTextArea > textarea,
.AutoGrowingTextArea::after {
  /* Identical styling required!! */
  border: 1px solid black;
  padding: 0.5rem;
  font: inherit;

  /* Place on top of each other */
  grid-area: 1 / 1 / 2 / 2;
}