dist/vue-inview.js
function (el, callback) {
  var size = el.length
  var i = 0
  for (i; i < size; i++) {
    callback(el[i], i)
  }
}
function (el, callback) {
  var size = el.length
  var i = 0
  for (i; i < size; i++) {
    callback(el[i], i)
  }
}
(el →  dom, callback → function)
- looping querySelectorAll