LineOffset is crashing with two identical coordinates in sequence

[SelaO]

I'm getting the error:

catch, Error: coordinates must contain numbers

when there are two or more identical coordinates in sequence:

          const arr1 = [[1,1], [1,1]]
          const x = lineString(arr1)
          const y = lineOffset(x, 0.001)

but this works:

          const arr1 = [[1,1],[12,12], [1,1]]
          const x = lineString(arr1)
          const y = lineOffset(x, 0.001)

It isn't mentioned in the docs that it's not ok to have identical points...

[stebogit]

Yeah, and the GeoJSON specs don't require LineString to include different positions. So I guess an error should not be thrown.

[SelaO]

This bug is with lineOffset not LineString @stebogit

[stebogit]

Sure, but I checked that to make sure that an error was not actually ok. What I mean is that if a valid LineString was actually required to have different positions, than an error thrown by lineOffset on an invalid input would not have been considered wrong, or a bug.

[mfedderly]

This isn't throwing an error any more, but it does return a bunch of NaN's that aren't helpful. This seems to root down to the processSegment method which calculates L to be 0 which gives us the NaN values.