working-manual-iterator.js

(function () {
  var array1, array2, array3, array4, gen, y, x;
  array1 = [50, 30, 70, 20];
  
  var obj = {
    idx: 0,
    next: function() {
      if (obj.idx >= array1.length) {
        return { done: true };
      }
      else {
        var i = obj.idx++;
        return { done: false, value: array1[i] };
      }
    },
  };
  
  var gen = () => ({
    [Symbol.iterator]: () => obj,
  });
  array2 = [];
  array3 = [];
  array4 = [];
  y = gen();
  for (x of y) {
    array2.push(x);
    if (x === 30) {
      break;
    }
  }
  for (x of y) {
    array3.push(x);
  }
  for (x of y) {
    array4.push(x);
  }
  console.log(array2, [50, 30]);
  console.log(array3, [70, 20]);
  return console.log(array4, []);
})()

s=k log w