babel es2015 class uncovered branch

[darrenmce]

it seems babel 6.14.0 introduced a new branch when transforming es2015 classes

https://github.com/babel/babel/commit/10cd6519d8f0374e8beb02a04f20da0123c52414

which (i think) results in a newly uncovered branch:

not sure where these types of issues are resolved, but I thought it would be worth bringing up here

[darrenmce]

in the mean time, for anyone else, the following pins got my build working without having to lower coverage parameters:

i had to explicitly include babel-plugin-transform-es2015-classes and babel-helper-replace-supers to be able to override the preset's semver

"babel-helper-replace-supers": "6.8.0",
"babel-plugin-transform-es2015-classes": "6.9.0",
"babel-preset-es2015": "6.13.2",

[jeffrifwald]

I believe this means the transformer added a branch but did not tell the source map generator about it. 6.14.0 added some checks to classes to allow them to be IE 9/10 compatible, so it is likely the source map is incorrect.

[jeffrifwald]

This is likely the culprit: https://github.com/babel/babel/pull/3527/files#diff-f78a336b572b82483a318406b52dd27dR349