index.js

const qs = el => document.querySelector(el)

const evt = (el, evtType, cb) => el.addEventListener(evtType, cb)

const val = el => qs(el).value.trim()

const greet = () => console.log('greet')

// const p = () => new Promise(res => res('ok'))

function exec() {
  const source = val('#source')

  new Function(source)()
}

document.addEventListener('DOMContentLoaded', () => {
  // evt(qs('#el'), 'click', () => console.log('ok'))
  evt(qs('#compile'), 'click', exec)
})