Function indexOf$1

01.GettingStarted/js/vue.js:4964–4972

* Native Array.indexOf uses strict equal, but in this * case we need to match string/numbers with custom equal. * * @param {Array} arr * @param {*} val

(arr, val)

   */

  function indexOf$1(arr, val) {
    var i = arr.length;
    while (i--) {
      if (looseEqual(arr[i], val)) {
        return i;
      }
    }
    return -1;
  }

  var checkbox = {