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Is reflect-metadata ESM-only? Can you require() it?

Polyfill for Metadata Reflection API

Last verified Sep 9, 2026 against reflect-metadata@0.2.2. Markdown · JSON

CommonJS CommonJS — require() works on every Node.js version we test

reflect-metadata ships CommonJS only. require("reflect-metadata") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "reflect-metadata" also works because Node.js and Bun can import CommonJS from ES modules, but only the default export is guaranteed; named imports depend on Node's static analysis of the module.

What to do

  1. require("reflect-metadata") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun.
  2. From ES modules use the default import: import reflectMetadata from "reflect-metadata"; then destructure. Named imports only work when Node.js can statically detect the exports.
  3. TypeScript: types are bundled; install nothing extra.
Latest
0.2.2 (Mar 29, 2024)
Module format
CommonJS
Last CommonJS version
0.2.2
TypeScript types
Bundled
Node engines
not declared
Weekly downloads
28.5M
License
Apache-2.0

Does reflect-metadata@0.2.2 actually load? Runtime test results

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

Runtimerequire("reflect-metadata")import "reflect-metadata"
Node.js 18✓ works✓ 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 reflect-metadata

ES modules (import)

import reflectMetadata from "reflect-metadata";

Named imports from a CommonJS package only work when Node.js can statically detect them. If a named import fails, use the default import and destructure.

CommonJS (require)

const reflectMetadata = require("reflect-metadata");

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 (19 versions; the newest 19 shown).

VersionsFormatFirst published
0.0.2 – 0.2.2CommonJSApr 14, 2015

Frequently asked

Is reflect-metadata ESM-only?

reflect-metadata@0.2.2 is a CommonJS package. reflect-metadata ships CommonJS only. require("reflect-metadata") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "reflect-metadata" also works because Node.js and Bun can import CommonJS from ES modules, but only the default export is guaranteed; named imports depend on Node's static analysis of the module.

Can I import reflect-metadata with ES module syntax?

Yes. import reflectMetadata from "reflect-metadata" works in Node.js and Bun because they support importing CommonJS modules. Named imports work only when Node.js can statically detect the exports.

Does reflect-metadata work in Bun?

Yes. import "reflect-metadata" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

Does reflect-metadata ship TypeScript types?

Yes. reflect-metadata bundles its own type declarations; no @types package is needed.

Links

Other commonjs packages

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