Do require.resolve for ES modules

Question

I need to resolve ES modules, imported via static import or function-like dynamic import, in a way similar to how CJS modules in node.js can be resolved using require.resolve(). Does anything like that exist for ES modules?

For example, if a Vue package have both vue.runtime.common.js and vue.runtime.esm.js. I need to get path to vue.runtime.esm.js. If package doesn't have one, I'd like to know it.

Titty

E.g. Vue package have both vue.runtime.common.js and vue.runtime.esm.js. I need path vue.runtime.esm.js one. If package doesn't have one, I'd like to know it. – Titty

Since ESM is agnostic as to package managers (e.g., the browser doesn't understand import 'someNpmPackage'), I don't think you will find an ES way. However, if you know what the path to the vue package will be relative to your module, you could use developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/… – Cottingham

Answer 1

As long as import.meta.resolve stays experimental, you can use createRequire to get back the require.resolve functionality in ES modules, e.g.

import { createRequire } from 'node:module';

const require = createRequire(import.meta.url);
const pathName = require.resolve('vue.runtime.esm.js');

Music

this requires a tsconfig.json with { "compilerOptions": { "module": "es2020" } } (via) – Lectern

@MilaNautikus This answer is actually for JavaScript, not TypeScript. – Music

A potential issue is that it picks package.json#exports["."].require instead of package.json#exports["."].import which may or may not be what you want. – Patagium

Answer 2

you can use import.meta.resolve()

here is an example from the node docs

(async () => {
  const dependencyAsset = await import.meta.resolve('component-lib/asset.js');
})();

note that you need to pass in --experimental-import-meta-resolve for this to work, as of node 14.3.0

Coryphaeus

this requires a tsconfig.json with { "compilerOptions": { "module": "es2020" } } (via) – Lectern

The flag --experimental-import-meta-resolve is still required today (v19.6.1). – Patagium

It's now, since 20.6.0, available without any flags: nodejs.org/en/blog/release/… – Patagium

But the argument parent (aka cwd) still requires a flag: nodejs.org/api/… – Patagium