arr1.js

  const test1 = [
      [1, 2, 3, '4'],
      [false, [1, 2], '6']
    ],
    test2 = [
      [
        [1, 78],
        [false, 'true'],
        [45, 'foo']
      ],
      [3, 5]
    ]

  arr = test2


  var addem = []

  function ea4(arr) {
    arr.forEach(element => {
      console.log('ELEMENT = ' + element)
      if (Array.isArray(element)) {
        console.log('returning')
        return ea4(element);
      }
      if (Number.isInteger(element)) {
        console.log(element)
        console.log('this ' + element + ' is ' + Number.isInteger(element))
        addem.push(element)
        console.log('add array now = ')
        console.log(addem)
        return element
      } else {
        console.log(element + ' will not be added ')
      }
    });
    result = addem.reduce(function (a, b) {
      return a + b;
    })
    console.log('total = ' + result)
  }

  ea4(arr);