If you have more logic than a couple of string comparisons, Bash is not the right tool for the job.
Like others say, "bash" is a hard tool to get right (and I'm not saying I do it right either, necessarily, but Greg's Wiki was real helpful!). I'm building a hybrid bash/python3 environment now (something I'll hopefully open-source at some point), and bash is just the "glue" to get things set up so most aspects of development can funnel through to python3 + other tools.
But ... things that make bash real useful:
* it's available everywhere (even in Windows with Ubuntu-18.04/WSL subsystem)
* it can bootstrap everything else you need
* it can wrap, in bash functions, aliases, and "variables" (parameters), the
real functionality you want to expose ... the
guts can be written in python3 or other tools
EDIT: I think there's a revised version of Greg's Bash Wiki in the works.
Python, sure, but replacing Bash with Node just seems like replacing a language crippled by its need to be backward compatible with (Bourne) sh with a language crippled by its need to be backward compatible with what Brandon Eich came up with in two weeks in 1995.
Python is the more direct substitute, though: it's built-in to almost every platform, and the Python 3 stagnation has even given us a consistent version: 2.7.
You're forgetting that bash really just calls other code. So you can combine two language's stdin/out functionality (eg, Python or Node) to pair code together. Sure, it won't be fast, but it can do quick wonders as an ad hoc data pipeline.