Buble compiler messing up sourcemap files with duplicate code
Not sure how to describe this issue, but in my project I'm using TypeScript and transpile down to ES6 & ES5. I then run the mocha tests on node.js and use Buble as the compiler. Same as done in this project - seen here: https://gitlab.com/Rich-Harris/buble/blob/master/package.json#L21
All this sounds good, but Buble are inserting an extra "use strict";
on top of already existing "use strict";
, so it look like this
`"use strict";`
`"use strict";`
Not sure why and how this happen, but this screw up the Istanbul coverage reporter. This was discovered by the author of Istanbul after a painfull bug hunt.
His findings can be seen here:
https://github.com/istanbuljs/istanbul-lib-instrument/issues/7#issuecomment-228548694