My experience of JS projects is that build tools are frequently ad-hoc. That is, there simply isn't a general build tool at all, but just a large pile of scripts calling under-documented libraries. Parallelization, caching and quite often even portability are just missing.
To justify this statement consider this blog post I wrote a while ago about porting GitHub Desktop (an Electron app) from its prior build/deployment system to Conveyor [1]. Conveyor is a tool for shipping desktop apps and is implemented as a single-purpose build system. The relevant part is this commit:
The amount of code that can be deleted is huge! Some of it is in-process code that isn't needed with Conveyor (setting up Squirrel etc), but a lot is just shell scripts that happen to be written in JS. Replacing that with a real build system not only simplifies the codebase but means the build steps are fully parallelized, fully incremental, easier to debug, portable (the build can run on any platform), progress is reported in a uniform way and so on.
So whilst the JS ecosystem's approach to build tools may be "simple" in some way, in the sense that there's no dominant build tool like Maven or Gradle, that simplicity does cost you in other ways.
To justify this statement consider this blog post I wrote a while ago about porting GitHub Desktop (an Electron app) from its prior build/deployment system to Conveyor [1]. Conveyor is a tool for shipping desktop apps and is implemented as a single-purpose build system. The relevant part is this commit:
https://github.com/hydraulic-software/github-desktop/commit/...
The amount of code that can be deleted is huge! Some of it is in-process code that isn't needed with Conveyor (setting up Squirrel etc), but a lot is just shell scripts that happen to be written in JS. Replacing that with a real build system not only simplifies the codebase but means the build steps are fully parallelized, fully incremental, easier to debug, portable (the build can run on any platform), progress is reported in a uniform way and so on.
So whilst the JS ecosystem's approach to build tools may be "simple" in some way, in the sense that there's no dominant build tool like Maven or Gradle, that simplicity does cost you in other ways.
[1] https://hydraulic.dev/blog/8-packaging-electron-apps.html (Disclosure: Conveyor is a commercial product made by my company)