[cromwellian]

Actually it is very relevant for JavaScript at Google, given Closure Compiler. Most of our JS apps are type checked, code split and optimized and Bazel is how we structure the module dependencies. The Bazel build rules define independent logical modules, and build processes prune unused dependencies, and calculate a dependency graph which is used to organize an optimal module structure, this is then used by Closure Compiler’s CrossModuleCodeMotion to further reduce size by moving methods and properties down to later modules.

Granted, JS isn’t incrementally built, but the dependency graph pruning (removing unused files from the build that aren’t imported or referenced in JS code) is parallelizable.

[venantius]

Yeah, JavaScript is a bit of an odd one out here, and I can obviously see the value in terms of providing a minimal build (in a way that's of less import to Ruby/Python users, say).

That said, it all depends what benefits you want to get out of Bazel. For us, incremental builds were the key thing we cared about - minimizing JAR size was important, but we already had a decently good handle on that.