Hello!

I'm raising an issue because I'm seeking guidance on whether TypeScript is intended to be used to ship .ts files inside node_modules. I'm asking as I'm one of the maintainers of ts-loader and this issue was raised on that very topic. It seems to have worked in the past (without any particular intention or effort on the part of ts-loader) but broke with TypeScript 2.0.

@basarat took a look into it and ended up reaching this conclusion:

I have the lost the will to implement it and would not recommend anyone to write a package that ships .ts + .js and instead people should use outDir + .d.ts + .js.
Again for those interested reasons, the following bad things happen if you ship .ts + .js files

• If your package is used in nodejs by someone using outDir, your package messes up other peoples outDir option.
• As new stricter TypeScript compiler options are implemented they cannot be used by people that use your package unless you update your package to compile with those options as well.

@basarat also suggested

We can provide an additional error message if path contains node_modules that says:
Since the file is in node_modules you should not need to recompile .ts files in node_modules and should contact the package author to request them to use --declaration --outDir.

I'm inclined to think this is a good idea and I was planning to implement this. Before I did so I wanted to see if this was in line with the way the TypeScript team intends the language to be used. I think this is probably encouraging good practice but I wondered if you could share a view on whether that's the case?

cc @jbrantly @HerringtonDarkholme