Suggestion: Transpile path mappings based module resolution imports to relative paths

[dsherret]

Taking example 2 from the original issue (#5039):

projectRoot
├── folder1
│   ├── file1.ts
│   └── file2.ts
├── generated
│   ├── folder1
│   └── folder2
│       └── file3.ts (Contains: import 'folder1/file2';)
└── tsconfig.json (with "baseUrl": ".")

When doing...

import 'folder1/file2';

...in file3.ts it current compiles to the same thing as above. Would it be possible if we could add a compiler option or some way that would convert this to the relative path? So it would transpile it to:

import './../../folder1/file2';

That way the paths don't have to be managed in two places. I couldn't find this discussed anywhere and didn't want to clutter the original issue so I'm opening this here.

[mhegazy]

Can you elaborate on the use case here.

[mhegazy]

please reopen if you have more information.

[LaurensRietveld]

@mhegazy : to avoid opening another issue with the same topic, I'd like to pitch in.
As far as I see, what @dsherret means is that the import * as something from 'folder1/file2' is transpiled to something like const something = require('folder1/file2') (assuming commonjs).
The transpiled JS won't work without some hacking around, i.e. duplicating the same functionality that typescript already has, but now for rewriting these javascript require statements.

I assumed that this conversion to relative paths was part of these new ts 2.0 features, but just like @dsherret I fail to find relevant documentation for this scenario

ps. Feel free to correct me if I reinterpret you incorrectly @dsherret ;)
pps. How I solved this (hacky): set the env variable NODE_PATH to the js directory (e.g. ./build/src), and set the base url to e.g. ./src. That way both TS and JS are looking in the correct location. This won't work when using the other new TS features such as paths though.

[dsherret]

Yes, basically I think it would be extremely nice if the emitter handled emitting the module specifier to a relative path if the module specifier is resolved using baseUrl, path mappings, or rootDirs.

Right now it emits import 'folder1/file2'; to have the same module specifier—'folder1/file2'. That means I have to configure the module loader to know the configuration in tsconfig.json... in this case "baseUrl": ".".

So current problems:

1. I have to configure "baseUrl": "." in TypeScript AND in my module loader configuration.
2. I have to hope that whatever module loader I'm using has support for the feature I use in tsconfig.json (baseUrl, path mappings, rootDirs).

It would be nice if the emitter would handle all this. That would mean that I would only need to keep this configuration in tsconfig.json.