load js script dynamically

dynamic-load-script.js

function loadJS(src) {
  let scriptEl = document.createElement('script')
  scriptEl.type = 'application/javascript'
  scriptEl.src = src
  const scriptLoadedPromise = new Promise((resolve, reject) => {
    scriptEl.onload = () => resolve() 
  })
  document.body.appendChild(scriptEl)
  return scriptLoadedPromise
}