Issue with arrow and a specific syntax

[gmarty]

I think the following syntax causes a bug with the arrow transform:

var a = function(b) {
  return {
    a: 1,
    b: 2,
  }[b];
};

More specifically the [b] after the return seems to be the cause of it.

[nene]

Thanks for reporting.

I see that the transform works without crashing, but results in invalid JavaScript:

var a = b => {
  a: 1,
  b: 2,
}[a];

it really should be:

var a = b => ({
  a: 1,
  b: 2,
}[a]);

Seems to be a bug in Recast library that handles turning the transformed AST back to code. It has a history of bugs related to the placement of parentheses.

[nene]

Recast has on open bug for a very similar-looking issue: benjamn/recast#351

[nene]

Fixed in 3.0.2