Improve sourceMappingURL regex

[swissspidy]

In my case, the build generated by webpack contained two references to sourceMappingURL that matched the existing regex.

The first one was in the middle of the minified script, looked something like ... 10)+1,l=R.substring(V)+(B?"//# sourceMappingURL="+B:""),J=new Blob([l],{type:"application/javascript"});...

The second one was the expected one at the very end of the file.

getSourceMap stopped at the first match, so ended up not finding the correct one.

Matching for a preceding newline before the //# sourceMappingURL comment resolves this, as it finds the correct comment and I get proper coverage reports now.

An alternative approach / further improvement would be to use a global match, eg.

const matches = source.match(/\s\/\/# *sourceMappingURL=(.*)/g);
const match = matches.at(-1);