Emit createRequire for TypeScript import = to match module: nodenext

[cspotcode]

Describe the feature

TypeScript's new module: nodenext will emit const require = createRequire() as necessary in ESM modules that have import = syntax. Without calling createRequire(), the code fails, because require is not defined in ES modules on nodejs.

import commonjs = require('commonjs'); 
import * as ecmascriptmodule from 'ecmascriptmodule';

commonjs, ecmascriptmodule;

When compiled by SWC using target=es2022 and module=es modules, I get: (playground link)

const commonjs = require('commonjs');
import * as ecmascriptmodule from 'ecmascriptmodule';
commonjs, ecmascriptmodule;

However, TypeScript will include a call to createRequire: (playground link)

import { createRequire as _createRequire } from "module";
const __require = _createRequire(import.meta.url);
const commonjs = __require("commonjs");
import * as ecmascriptmodule from 'ecmascriptmodule';
commonjs, ecmascriptmodule;

Is there any way to tell SWC to emit this createRequire call?

Babel plugin or link to the feature description

No response

Additional context

No response

[cspotcode]

Related to #4679

I may have some time for this soon; can anyone point me in the right direction to implement this fix?

In ts-node I'm hoping to ship support for TS's new nodenext/node16 modes -- mts, mjs, cts, cjs. But this is a blocker since it means the swc backend can't emit correct mts.

[kdy1]

First, you will have to add a module like nodenext to https://github.com/swc-project/swc/tree/fe1e62a5e7a4a0037ba8d158879fb68bf9c14520/crates/swc_ecma_transforms_module/src or alternatively add nodenext: bool to common js pass (https://github.com/swc-project/swc/blob/9a027ba7c2146ac4dbfce9478d1a259ff491a11f/crates/swc_ecma_transforms_module/src/common_js.rs)

For the latter, you would need to wrap util::Config like

swc/crates/swc_ecma_transforms_module/src/amd.rs

Lines 64 to 72 in 9a027ba

	#[derive(Debug, Clone, Default, Serialize, Deserialize)]
	#[serde(deny_unknown_fields, rename_all = "camelCase")]
	pub struct Config {
	#[serde(default)]
	pub module_id: Option<String>,
	#[serde(flatten, default)]
	pub config: util::Config,
	}

---

After then, you can add an import with a specifier named createRequire, using private_ident! (like

swc/crates/swc_ecma_transforms_module/src/common_js.rs

Line 466 in 9a027ba

let ident = ident.unwrap_or_else(|| private_ident!("_default"));

).
Once you have it, you can add imports to the module, and replace/wrap require calls with createRequire

[cspotcode]

I've hit a snag and need some guidance.

This createRequire transformation should only happen when module type = es6, not Commonjs. So I implemented an es6 transformation that checked for the presence of any TsImportEqualsDecl and, when found, created the necessary import of createRequire and const require = createRequire(import.meta.url);

The problem is, typescript stripping runs before the es6 transformation. This means TsImportEqualsDecl does not exist by the time es6 runs.

How should the typescript stripping pass tell the es6 pass that a TsImportEqualsDecl was stripped?

I thought about the typescript stripping doing the createRequire, but the problem is that for module=Commonjs, we should not do that.

[magic-akari]

I believe this feature is already available in swc.

swc playground

[kdy1]

Thank you!

[swc-bot]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.