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Is internmap ESM-only? Can you require() it?

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Last verified Sep 9, 2026 against internmap@2.0.3. Markdown · JSON

ESM-only ESM-only since 2.0.0 — last CommonJS version is 1.0.1

internmap dropped its CommonJS build in 2.0.0 (June 2021). The last version with a plain require()-able CommonJS entry is 1.0.1, published Mar 10, 2021.

On Node.js 20.19+, 22.12+ and newer, require("internmap") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. On Node.js 18, which has no require(esm), require("internmap") fails with ERR_REQUIRE_ESM.

What to do

  1. On Node.js 20.19+, 22.12+ and newer, require("internmap") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26.
  2. From a CommonJS file, use a dynamic import inside an async function: const internmap = await import("internmap"). That works on every Node.js version the package supports (>=12).
  3. If you need a synchronous require() or run Node.js 18: npm install internmap@1.0.1, the last CommonJS release (published Mar 10, 2021).
  4. TypeScript: no types are available for internmap; declare the module yourself if you need them.
Latest
2.0.3 (Sep 20, 2021)
Module format
ESM-only
Last CommonJS version
1.0.1
ESM-only since
2.0.0 (Jun 3, 2021)
TypeScript types
None
Node engines
>=12
Weekly downloads
79.5M
License
ISC

Does internmap@2.0.3 actually load? Runtime test results

Installed and executed on Sep 9, 2026 with require("internmap") from a CommonJS file and import "internmap" from an ES module.

Runtimerequire("internmap")import "internmap"
Node.js 18✗ failsERR_REQUIRE_ESM✓ works
Node.js 20✓ works✓ works
Node.js 22✓ works✓ works
Node.js 24✓ works✓ works
Node.js 26✓ works✓ works
Bun 1.4.0✓ works✓ works

How to import internmap

ES modules (import)

import * as internmap from "internmap";

Namespace import shown because the ESM entry may have no default export; use named imports for what it exports.

CommonJS (require)

// Node.js 20.19+, 22.12+ and newer (verified):
const internmap = require("internmap");

// Any Node.js version the package supports (>=12), from an async function:
async function main() {
  const internmap = await import("internmap");
}

// Or pin the last CommonJS release:
// npm install internmap@1.0.1

Module format by version

Derived from the type, main and exports fields of every stable release on npm, corrected where a runtime test of that version contradicted them (6 versions; the newest 6 shown).

VersionsFormatFirst published
2.0.0 – 2.0.3ESM-onlyJun 3, 2021
1.0.0 – 1.0.1CommonJSJan 21, 2021

Frequently asked

Is internmap ESM-only?

internmap@2.0.3 is ESM-only. internmap dropped its CommonJS build in 2.0.0 (June 2021). The last version with a plain require()-able CommonJS entry is 1.0.1, published Mar 10, 2021.

Which version of internmap still supports CommonJS / require()?

1.0.1 is the last version of internmap with a CommonJS build. Install it with "npm install internmap@1.0.1". Every version from 2.0.0 on is ESM-only.

How do I use internmap from a CommonJS file?

From a CommonJS file, use a dynamic import inside an async function: const internmap = await import("internmap"). That works on every Node.js version the package supports (>=12). On Node.js 20.19+, 22.12+ and newer, require("internmap") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Alternatively pin internmap@1.0.1.

Does internmap work in Bun?

Yes. import "internmap" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

Does internmap ship TypeScript types?

No. internmap ships no type declarations and there is no @types package for it.

Links

Other esm-only packages

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