Trouble mixing typescript and javascript files

[wgottschalk]

I'm having trouble getting dependency-tree to follow ts imports from js files. For instance if I define:

// one.ts
import {two} from './two';

export function one() {
  console.log('one');
  two()
}

// two.js
import {three} from './three';

export function two() {
  console.log('two');
  three()
}

// three.ts
import {four} from './four';

export function three() {
  console.log('three');
  four()
}

// four.js
export function four() {
  console.log('four');
}

when I run dependency-tree on the source code:
dependency-tree --directory='.' one.ts

I get the following output:

{
  "one.ts": [
    "two.js"
  ],
  "two.js": []
}

But I'm expecting dependency-tree to be able to resolve the typescript import from a javascript file. Is there any documentation on how to do this? It seems like a common enough case.

[mrjoelkemp]

Thanks for filing the issue. This is a slightly tough one. Right now, each file is processed in isolation for its module type. So a .js file assumes it's one of the js module types (AMD, CJS, ES6). In this case, it's ES6, so it'll have to guess what the file extension should be. Currently, resolution logic isn't set up to check for several extensions when trying to guess what the extension of the module path is. This is similar to how it would work if you tried to use pure commonjs resolution and not the typescript compiler for your project.

One way that should work in the interim is putting the file extension in the import.

Perhaps a slightly better solution is to check for the existence of a typescript config and then use typescript resolution all the way across the codebase. That would work in your case, but it doesn't cover mixed codebases (where part of it uses TS and another part uses some other incompatible compiler/resolver). If you were to supply both a typescript config and a requirejs config, we wouldn't know what to use with this approach. Currently, we'd sniff the module type of the file itself, determine that it's AMD, then use the requirejs config.

Happy to hear other suggestions. I know that changing application code just for tooling is not ideal.

[mrjoelkemp]

Closing due to inactivity. Cheers!

[mrjoelkemp]

@wgottschalk This will work if you have the allowJs compiler option turned on in your TS config. #122 is adding a test to prove it.

Big props to @pastak for putting that support into a recent filing-cabinet release: dependents/node-filing-cabinet@826443a#diff-e727e4bdf3657fd1d798edcd6b099d6e092f8573cba266154583a746bba0f346R282.