Except, as pointed out, there is no lack of coverage in my example. All lines are 'covered', and no line is left unexecuted. So by definition, there is no 'lack of coverage' from the perspective of lines. The key is to not think about 'coverage' as a metric on lines, and instead think of 'coverage' as a metric on program states. However, that's generally not what people think of when 'code coverage' is mentioned unless something specific like 'program space coverage' or 'code state coverage'.

Keep in mind that this can be really hard though since even very simple code can have a large state space.

Also, if you have a favorite tool that does program space coverage for node.js projects, it might be helpful to mention it here so that others can benefit. Most of the tools for node that I know are only line coverage.