Run results for: for of over a small array

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36

Browser: Chrome 79

Operating system: Linux

Device Platform: Desktop

Date tested: 4 years ago

Script Preparation code:

function meow() {
  return [1, 2, 42, 52];
  
}

Tests:

native for of
const foo = meow() foo.push(1337); let blah; for (let i of foo) { blah = i; }
babel for of
const foo = meow(); foo.push(1337); let blah; var _iteratorNormalCompletion = true; var _didIteratorError = false; var _iteratorError = undefined; try { for (var _iterator = foo[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) { let i = _step.value; blah = i; } } catch (err) { _didIteratorError = true; _iteratorError = err; } finally { try { if (!_iteratorNormalCompletion && _iterator.return != null) { _iterator.return(); } } finally { if (_didIteratorError) { throw _iteratorError; } } }
babel for of loose
var foo = meow(); foo.push(1337); let blah; for (var _iterator = foo, _isArray = Array.isArray(_iterator), _i = 0, _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) { var _ref; if (_isArray) { if (_i >= _iterator.length) break; _ref = _iterator[_i++]; } else { _i = _iterator.next(); if (_i.done) break; _ref = _i.value; } var i = _ref; blah = i; }
indexed for loop
const foo = meow() foo.push(1337); let blah; for (let k = 0; k < foo.length; k++) { blah = foo[k]; }