shims for __dirname so one code can output to both esm and cjs

[wighawag]

Feature request

shim for _dirname or other features like this

This is something tsup supports (and esbuild) : https://github.com/egoist/tsup/blob/00188a0dc848c48fac45de245d1e021f370a84a3/src/cli-main.ts#L91

Motivations

My project export to both cjs and esm and being able to use the same code for both is needed

Alternatives

No response

Additional context

No response

Contributions

• [ ] I plan to open a pull request for this issue
• [ ] I plan to make a financial contribution to this project

[privatenumber]

You mean you'd like to use __dirname in ESM?

CommonJS is being phased out by Node in favor of the ESM standard, so it might be better to shim import.meta.url for CJS. I haven't tested yet but this might even work in CJS already.

[wighawag]

I ended up using the following

import {dirname} from 'path';
import {fileURLToPath} from 'url';
const __dirname = dirname(fileURLToPath(import.meta.url));

and it indeed seems to be working

in the cjs it get transformed into :

path.dirname(url.fileURLToPath((typeof document === 'undefined' ? require('u' + 'rl').pathToFileURL(__filename).href : (_documentCurrentScript && _documentCurrentScript.src || new URL('index.cjs', document.baseURI).href))));

So I guess this works, not sure why it is that verbose though

[privatenumber]

There are more concise options: https://stackoverflow.com/questions/46745014/alternative-for-dirname-in-node-js-when-using-es6-modules

const __dirname = import.meta.dirname;
const __filename = new URL('', import.meta.url).pathname;
const __dirname = new URL('.', import.meta.url).pathname;

Anyway, closing as import.meta.url should be used.