Can't assign let variables inside of closures

[jclem]

Not really a closure, but this most clearly demonstrates the issue:

(function() {
  let foo = 'bar';

  [true].forEach(function() {
    foo = 'baz';
  });

  console.log(foo);
});

Compiles to:

"use strict";
(function() {
  var _foo = 'bar';

  [true].forEach(function(_foo) {
    return function() {
        _foo = 'baz';
      };
  }(_foo));

  console.log(_foo);
});

Should be more like:

"use strict";
(function() {
  var _foo = 'bar';

  [true].forEach(function() {
    _foo = 'baz';
  });

  console.log(_foo);
});

[UltCombo]

Any progress on this? IMHO this is a rather serious issue.

Here's a more elaborated test case:

for (let x = 0; true;) {
    (function() {
        x = 1;
    }());
    (function() {
        assert.equal(x, 1);
        x = 2;
    }());
    assert.equal(x, 2);
    break;
}

[sebmck]

It's a current limitation of the current let scoping transformer (not being able to reassign let variables inside of closures). I haven't gotten around to rewriting it because I've been busy with a code generator rewrite.

[UltCombo]

Thanks for the amazingly quick reply. =] I've been fiddling with the let transformer a bit and just realized that it will most likely require a huge rewrite.

[UltCombo]

Just curious, but what are the plans for this (if any)? Use try/catch, or a state machine like Traceur's?

[sebmck]

Definently not try/catch, probably something similar if not the same as Traceur.

[UltCombo]

Traceur's generated code looks quite horrible considering break/continue/return in for loops, but then again, nested try/catches aren't anything nice either. Thanks for the lightning-fast replies. =]

[sebmck]

Fixed when 287cbbb is merged.

[UltCombo]

yay, nice!

[sebmck]

Fixed as of 1.11.0

[UltCombo]

Awesome, thanks!