I'm working on a library/cli-tool for bundling dependency licenses into a single file. Currently, I'm trying to collect licenses of: direct dependencies, transitive-dependencies and direct dev-dependencies.
In other words, I'm trying to collect licenses of packages, that are installed in node_modules. Transitive dev-dependencies are not installed by the package manager, because of the very nature of dev-dependencies.
I'm worried, whether or not code portions of those transitive dependencies somehow can be included in installed packages.
For example: Project "A" depends on Package "B". Package "B" has Transpiler "C" as a dev-dependency. Code generated by Transpiler "C" in Package "B" includes not only simple transpilation result, but also some polyfill for a function, that is not available in older browsers, from Transpiler "C". But, because Transpiler "C" is a transitive dev-dependency, it is not installed in node_modules of Project "A", so without manually installing it, Transpiler "C"-s license cannot be properly obtained, can it? Even if we could, we will have to look for Transpiler "C"-s dependencies/dev-dependencies too, etc, etc.
In this hypothetic case, we have only one transitive dev-dependency, but, in real-world scenarios, there could be hundreds. There could be several versions of the same package defined as a transitive dev-dependency in different packages. By manually installing transitive dev-dependencies for collecting license information, these transitive dev-dependencies could have their own dev dependencies, which will be needed to be installed too. This process will have to be repeated until all transitive dev-dependencies of all transitive dev-dependencies are installed.
Question is: Should I care for collecting license information about transitive dev-dependencies? And if I should, to which point?
I already care for regular transitive-dependencies, but I'm worried for transitive dev-dependencies.