[Feature] Add ability to output explicit indexes

[jacobbogers]

Hello,

Example: this (transpiled) code loads the index.js file

import  {  some_function } from '../siblingdir';   // there is an index.js in the "siblingdir"

If i try to use this in an es6 fashion I will get ERR_UNSUPPORTED_DIR_IMPORT Because it is not possible in the esm standard to do directory imports, it has to be fully specified import { some_function } from '../siblingdir/index.js

I wonder if there is an options where it detects:

• if it is a directory, add an /index.js suffix
• if it is a normal file add the explicit extension '.js'

Cheers,

[jacobbogers]

https://nodejs.org/api/esm.html#esm_mandatory_file_extensions

Mandatory file extensions

A file extension must be provided when using the import keyword to resolve relative or absolute specifiers. Directory indexes (e.g. './startup/index.js') must also be fully specified.

This behavior matches how import behaves in browser environments, assuming a typically configured server.

[nonara]

No option at the moment. Would be pretty easy to implement, though. I'd be open to a PR as a useExplicitIndexes option.

I was also considering adding useExplicitExtensions. Another esm reconciliation feature.

Like I said, PR welcome! Otherwise I may add it when I have some time.

[jacobbogers]

I found a "how to build an plugin" doc, I am reading it

[nonara]

Mandatory file extensions

Yep. That's the reason for the second option. Esm is a pain 😄

[nonara]

Eh. It should be pretty easy on both fronts, and there don't seem to be any good solutions out there for this in esm.

I'll try to knock these out tomorrow.

[jacobbogers]

How is it going?

[nonara]

Finished. Just working on integrating with tests. I opted for adding a config property: outputMode which is either commonjs | esm. When not specified, it's commonjs by default.

Behaviour is to add explicit extension and index if in esm mode. And, for declaration file output, outputMode will always set itself to commonjs, as I do not believe .d.ts has an esm-specific difference. Do you know if that's correct?

[jacobbogers]

Super thank you,

About your question:

I do not believe .d.ts has an esm-specific difference. Do you know if that's correct?

Honestly I do not know this, I dont think *.d.ts file have any knowledge about esm or commonjs

What about the *.d.ts.map files? Are they generated after all "transpilations" runs? (I think so, but I ask just to make sure)

[nonara]

No problem!

Documentations indicates that TS uses their own "ES-like" syntax for modules, so I think we're covered. As for map files, those should be generated post-transform.

Waiting 'til tomorrow on another PR to do an official release, but I've published an alpha. Would you mind checking if it works for you?

{
  "devDependencies": {
    "typescript-transform-paths": "3.4.0-alpha"
  }
}

[jacobbogers]

Would you mind checking if it works for you?

Yes,I am checking it right now

[jacobbogers]

Maybe I am doing something wrong, but It did not work for me

In my node_modules I have installed the correct verison

{
  "name": "typescript-transform-paths",
  "version": "3.4.0-alpha",

My tsconfig.json looks like so:

"compilerOptions: {
      "plugins": [
            {
              "name": "typescript-eslint-language-service"
            },
            {
              "transform": "typescript-transform-paths",
              "useExplicitIndexes": true,
              "useExplicitExtensions": true
            },
            {
              "transform": "typescript-transform-paths",
              "afterDeclarations": true
            }
}

But the transpiled code not showing explicit .js or /index.js additions in the path

import { fixup } from '../fixup';   // no .js extension
import { IRNG } from '../irng';
import { IRNGTypeEnum } from '../irng-type';
.
.

Maybe I am configuring it incorrectly, I do not know for sure.

[nonara]

Sorry, I should have specified. "outputMode": "esm" not useExplicitIndexes or useExplicitExtensions

[jacobbogers]

ok Checking with your parameters

[jacobbogers]

Works, shows explicit /index.js at the end of a directory import

'use strict';
export * from "./distributions/beta/index.js";
export * from "./distributions/binomial/index.js";
export * from "./distributions/binomial-negative/index.js";
export * from "./distributions/cauchy/index.js";

and also .js for individual regular files

export { dbinom } from "./dbinom.js";
export { pbinom } from "./pbinom.js";
export { qbinom } from "./qbinom.js";
import { rbinomOne } from "./rbinom.js";
import { globalUni } from "../../rng/global-rng.js";
import { repeatedCall64 } from "../../r-func.js";

Super thank you!! Now I can release esm version