JSFX equivalent to AA's "Generate Tones" - how to build?

Hi, I'm a long-time Reaper user but have never coded...so a total JS newbie.
I have an interest in pure waveforms, related to psychoacoustics, and have used Adobe Audition's Generate Tones function for years.
Generate Tones is limited, but it's very precise, and can use multiple oscillators.
I want to move those features into Reaper, to able to use them in real-time and to automate all parameters from a single plugin.
AA's Generate Tones is basically a rendering engine and I've reached the limits of that.
I built a simple equivalent in MaxMSP - that seemed quite trivial to do, but I need to be in a timeline-based DAW.
I've done some little hacks to the JS synthesis/tonegenerator and the ones by Tale, to try to see how JS oscillators work.
But can anyone steer me a bit, as to how to make such JS tonegens multiple-oscillator?
Do I just copy-paste existing code and rename variables as I go, and then make some sort of mixer, or is there a more elegant route?
I don't need any MIDI, so no classic poly synth stuff or envelopes or filters etc, just an expanded test-tone concept.
Thanks

JSFX equivalent to AA's "Generate Tones" - how to build?