Node.js v20.6+ no longer supports the loader API in favour of the register API

[doichev-kostia]

According to the node.js release notes for node 20.6 the experimental loaders API was deprecated in favour of the register API. Because of that, we need to use node --import register.js file.ts instead of node --loader @swc-node/register/esm file.ts.

Currently, it's not possible or not mentioned in the docs how to solve this issue with @swc-node/register and the error the users may have is

node --loader @swc-node/register/esm ./src/main.ts

(node:68547) ExperimentalWarning: `--experimental-loader` may be removed in the future; instead use `register()`:
--import 'data:text/javascript,import { register } from "node:module"; import { pathToFileURL } from "node:url"; register("%40swc-node/register/esm", pathToFileURL("./"));'
(Use `node --trace-warnings ...` to show where the warning was created)

node:internal/process/esm_loader:40
      internalBinding('errors').triggerUncaughtException(
                                ^
Error: Bindings not found.

Reproduction and workaround

I've added a repo with the reproduction and possible workaround influenced by tsx.

[valeneiko]

You can create a file to register @swc-node hooks:

import {register} from 'node:module';
import { pathToFileURL } from "node:url";

register('@swc-node/register/esm', pathToFileURL('./'));

And use it in the --import flag:

node --import ./register.js ./src/main.ts

[barthuijgen]

Not wanting to create an extra entrypoint file I've found the inline option to work fine as well.

{
  "scripts": {
    "dev": "node --import 'data:text/javascript,import {register} from \"node:module\";import {pathToFileURL} from \"node:url\";register(\"%40swc-node/register/esm\",pathToFileURL(\"./\"));' src/main.ts"
  }
}

This does make it quite verbose I hope a solution will emerge that lets us do this with a shorter syntax.

[yeliex]

I have created a pr to support this #748

before merged, try use https://npmjs.com/swc-register-esm temporary

[ehaynes99]

Note: looks like they backported it, because node 18 also emits this warning.