const todos = [
  'buy milk',
  'clean kitchen',
  'learn js',
]

const appendItem = (item) => {
  const el = document.createElement('li')
  const elText = document.createTextNode(item)
  el.appendChild(elText)
  document.getElementById('list1').appendChild(el)
}

/*
Here is a simple way to apply the `appendItem` function
to each item in the array:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach
*/
todos.forEach(appendItem)