Labels should be minified

[ooflorent]

Currently labels are not minified:

Input:

abc: for (var a = [1, 2, 3, 4], i = 0; i < a.length; ++i) {
  continue abc
}
def: for (var a = [1, 2, 3, 4], i = 0; i < a.length; ++i) {
  for (var j = i; j < a.length; ++j) {
    if (i + j > 7) {
      continue def
    }
  }
}

Current output:

abc:for(var a=[1,2,3,4],i=0;i<a.length;++i)continue abc;
def:for(var a=[1,2,3,4],i=0;i<a.length;++i)for(var j=i;j<a.length;++j)if(7<i+j)continue def;

Expected output:

for(var a=[1,2,3,4],i=0;i<a.length;++i)continue;
a:for(var a=[1,2,3,4],i=0;i<a.length;++i)for(var j=i;j<a.length;++j)if(7<i+j)continue a;

[hzoo]

Hey @ooflorent! We really appreciate you taking the time to report an issue. The collaborators
on this project attempt to help as many people as possible, but we're a limited number of volunteers,
so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack
community that typically always has someone willing to help. You can sign-up here
for an invite.

[boopathi]

We are explicitly NOT mangling labels and one of the reasons was babel had labels and variables as bindings and these label bindings were interfering with other variables in the scope. This has changed in babel in babel/babel#4758. Should revisit that in mangler.