Show print-friendly HTML details elements' content with only a few lines of JavaScript

[rpearce]

const mql = window.matchMedia('print')

mql.addEventListener('change', (event) => {
  const detailEls = document.querySelectorAll('details')

  detailEls.forEach(detailEl => {
    if (event.matches) {
      detailEl.open = true
    } else if (detailEl.open) {
      detailEl.open = false
    }
  })
})