Because web developers seem to be unfamiliar with software that has solved their problems decades ago in languages that aren't JavaScript.
is a very silly reason. A build system is a system and needs to be learnt, whether it's a library in JS or a domain-specific language.
(That a JS-based build system shares syntax with JS is not relevant, since the useful denotation is JS syntax->build script, not JS syntax->JS code (unless you're debugging the build system itself). I contend that the denotation JS syntax->build script is no easier, and is perhaps more difficult, to learn than the denotation build syntax->build script, as it is, by definition, confusingly similar to the syntax for JS code!)
Really? gulp build step dependencies look almost exactly like AMD dependencies.
Edit: my wife has also asked me to ask you "will it scale?"
Are you implying that my parenthetical is invalid because the DSL has JS-like syntax? You must have missed where I said "no easier" and "perhaps more difficult". If the DSL's syntax is identical to that of the library's, then clearly the denotation of the library is no easier to understand than that of the DSL – they are identical.
Was your wife's question supposed to be funny?
They're used widely used in things with a front end.
> I infer that one must be implemented as a JS library, and one must be a DSL with JS-like syntax.
No, they're both JS libraries. See Google.
That being said, javascript build systems just repeat the mistakes made by make, instead of learning from those mistakes.
[0] http://gittup.org/tup/build_system_rules_and_algorithms.pdf
Make is from 1977, and is pretty rare for web developers. gulp was designed as a grunt replacement, anyone familiar with the former can learn the latter.
I love jslint, I love checking for insecure npm modules, and the other things this module provides seem good too, but having a build system doesn't preclude any of those.