Load script by Promise

load-script-by-promise

const loadScriptByPromise = (url: string) =>
  new Promise(resolve => {
      const head = document.getElementsByTagName('head')[0]
      const script = document.createElement('script')
      script.type = 'text/javascript'
      script.addEventListener('load', function listener(){
        this.removeEventListener('load', listener)
        resolve(script)
      })
      script.src = url
      head.appendChild(script)
    })
  }