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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. 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 you can require() on every Node.js version, including 18 and older, is 1.0.1, published Mar 10, 2021.

On Node.js 20.19+, 22.12+ and every newer release, require("internmap") works anyway: Node can load synchronous ES modules through require(). Verified on Node 20, 22, 24, 26. Node.js 18 and older still fail with ERR_REQUIRE_ESM.

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✓ works✓ works

How to import internmap

ES modules (import)

import internmap from "internmap";

CommonJS (require)

// Node.js 20.19+ / 22.12+ / newer (package has no top-level await):
const internmap = require("internmap");

// Any Node.js version:
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 (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 you can require() on every Node.js version, including 18 and older, 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?

Use a dynamic import: const mod = await import("internmap"). On Node.js 20.19+, 22.12+ and newer, a plain require("internmap") also works for ESM packages that do not use top-level await. Alternatively pin internmap@1.0.1.

Does internmap work in Bun?

Yes. import "internmap" loaded successfully in Bun 1.4 on Sep 9, 2026.

Does internmap ship TypeScript types?

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

Links

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