I got way into webaudio and made some libraries to that effect. For something close to TFA, try wafxr:

https://fenomas.github.io/wafxr/

It can export wav files, but its main purpose is to generate code snippets for playing the sound effect through webaudio, underneath using a much more general library. But people familiar with audio synthesis might prefer just using the underlying dependency directly - it basically turns arbitrary config into webaudio. This playground shows how it works:

https://fenomas.github.io/wasgen/