Testing require(esm)

As of v22.12.0, Node.js added support for synchronous require of ESM dependency graphs. This feature is a huge win for the interoperability of the CommonJS and ESM module ecosystems in Node, but toolchains have yet to provide first-class support for this feature.

For example, TypeScript 5.7.3 (latest release) currently throws an error even with compilerOptions.moduleResolution set to nodenext (ref microsoft/TypeScript#60534).

The current file is a CommonJS module whose imports will produce 'require' calls; however, the referenced file is an ECMAScript module and cannot be imported with 'require'. Consider writing a dynamic 'import("global-directory")' call instead.
  To convert this file to an ECMAScript module, change its file extension to '.mts' or create a local package.json file with `{ "type": "module" }`.ts(1479)

In this demo repository, I'm focusing on how the current versions of Jest (29.7.0) and Vitest (3.0.3) handle interop for require(esm).

✅ The code in index.ts runs via tsx

npm start
> require-esm-test@1.0.0 start
> npx tsx index.ts

/Users/erick.zhao/.nvm/versions/node/v22.13.0

❌ Jest fails

npm run test:jest

    /Users/erick.zhao/Developer/dump/require-esm-test/node_modules/global-directory/index.js:1
    ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){import process from 'node:process';
                                                                                      ^^^^^^

    SyntaxError: Cannot use import statement outside a module

✅ Vitest passes

npm run test:vitest

> require-esm-test@1.0.0 test:vitest
> npx vitest run index-vitest.spec.ts


 RUN  v3.0.3 /Users/erick.zhao/Developer/dump/require-esm-test

stdout | index-vitest.spec.ts
/Users/erick.zhao/.nvm/versions/node/v22.13.0

 ✓ index-vitest.spec.ts (1 test) 1ms
   ✓ index > should return true