renderless component example

index.js

import React from 'react'

export default function PrismHack() {
  React.useEffect(() => {
    const diffs = [...document.querySelectorAll('.language-diff-javascript')]

    diffs.forEach(diff => {
      diff.setAttribute('class', 'language-diff-javascript diff-highlight')
    })
  }, [])

  return null
}