iterator

output.6to5.txt

// output
10

// generated code
"use strict";

var numbers = regeneratorRuntime.mark(function callee$0$0(start, end) {
  var i;
  return regeneratorRuntime.wrap(function callee$0$0$(context$1$0) {
    while (1) switch (context$1$0.prev = context$1$0.next) {
      case 0:
        i = start;
      case 1:
        if (!(i <= end)) {
          context$1$0.next = 7;
          break;
        }
        context$1$0.next = 4;
        return i;
      case 4:
        i++;
        context$1$0.next = 1;
        break;
      case 7:
      case "end":
        return context$1$0.stop();
    }
  }, callee$0$0, this);
});

var sum = 0;
var iterator = numbers(1, 4);

for (var _iterator = iterator[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
  var i = _step.value;
  sum += i;
}

console.log(sum);

output.traceur.txt

// traceur
10

// generated code
$traceurRuntime.ModuleStore.getAnonymousModule(function() {
  "use strict";
  var numbers = $traceurRuntime.initGeneratorFunction(function $__2(start, end) {
    var i;
    return $traceurRuntime.createGeneratorInstance(function($ctx) {
      while (true)
        switch ($ctx.state) {
          case 0:
            i = start;
            $ctx.state = 7;
            break;
          case 7:
            $ctx.state = (i <= end) ? 1 : -2;
            break;
          case 4:
            i++;
            $ctx.state = 7;
            break;
          case 1:
            $ctx.state = 2;
            return i;
          case 2:
            $ctx.maybeThrow();
            $ctx.state = 4;
            break;
          default:
            return $ctx.end();
        }
    }, $__2, this);
  });
  var sum = 0;
  var iterator = numbers(1, 4);
  for (var $__0 = iterator[$traceurRuntime.toProperty(Symbol.iterator)](),
      $__1 = void 0; !($__1 = $__0.next()).done; ) {
    var i = $__1.value;
    {
      sum += i;
    }
  }
  console.log(sum);
  return {};
});
//# sourceURL=traceured.js

sum_of_numbers.es.js

let numbers = function*(start,end) {
  for(let i=start; i <= end; i++) {
    yield i;
  }
}

let sum = 0;
let iterator = numbers(1,4);

for (let i of iterator) {
  sum += i;
}

console.log(sum);