Lines resolved to wrong file silently

[corvidism]

Hi, I ran into a possible bug: when I try to resolve a position in a file that isn't covered by an inline source map mapping, the .resolve() method returns an object which points to the file itself instead of its source, and doesn't signal this "resolution failure" in any way.

I forked the repo and wrote some (failing) tests that demonstrate the problem: https://github.com/corvidism/get-source/pull/1/files

The TMP tests show this on a file where I discovered it. It's compiled from typescript, and it looks like the typescript compiler doesn't include the leading spaces in the mappings => when I try to resolve a line from column=1 (I don't have the column number), the resolution fails.

Obviously, the ideal would be if it resolved, but it should at least warn that the resolution failed. As it is, there's no way to detect it. (That, and perhaps the sourceFile could be set anyway? I mean, the filename is there, even if the mapping failed...)

[corvidism]

I dove into the code and unfortunately, I think the resolution failure itself is caused by this bug in source-map: mozilla/source-map#261 Which looks a bit abandoned, sigh.

Still, it would be nice if this module could at least signal that this error happened. Maybe use the error key?