import-script.js

export default function importScript(src) {
  return new Promise((resolve, reject) => {
    const loaded = Boolean(document.querySelector(`script[src="${src}"]`))
    if (loaded) return resolve()

    const script = document.createElement('script')
    script.type = 'text/javascript'
    script.src = src
    script.async = true

    script.onload = () => resolve()
    script.onerror = reject

    const head = document.getElementsByTagName('head')[0]
    head.appendChild(script)
  })
}