canirequire

canirequire › Dual (CommonJS + ESM) › tslib

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

Runtime library for TypeScript helper functions

Last verified Sep 9, 2026 against tslib@2.8.1. Markdown · JSON

Dual (CommonJS + ESM) Dual package — require() works on every Node.js version we test; import works too

tslib publishes both a CommonJS entry and a native ESM entry (ESM added in 1.14.0). require("tslib") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "tslib" works alongside it.

What to do

  1. Nothing to change. require("tslib") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import * as tslib from "tslib" works alongside it; use named imports for what the ESM entry exports.
  2. TypeScript: types are bundled; install nothing extra.
Latest
2.8.1 (Oct 31, 2024)
Module format
Dual (CommonJS + ESM)
Last CommonJS version
2.8.1
Native ESM since
1.14.0
TypeScript types
Bundled
Node engines
not declared
Weekly downloads
374.4M
License
0BSD

Does tslib@2.8.1 actually load? Runtime test results

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

Runtimerequire("tslib")import "tslib"
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 tslib

ES modules (import)

import * as tslib from "tslib";

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

CommonJS (require)

const tslib = require("tslib");

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 (45 versions; the newest 45 shown).

VersionsFormatFirst published
2.0.2 – 2.8.1Dual (CommonJS + ESM)Oct 6, 2020
2.0.0 – 2.0.1CommonJSMay 13, 2020
1.14.0 – 1.14.1Dual (CommonJS + ESM)Oct 6, 2020
1.0.0 – 1.13.0CommonJSJun 28, 2016

Frequently asked

Is tslib ESM-only?

tslib@2.8.1 ships CommonJS and ESM builds. tslib publishes both a CommonJS entry and a native ESM entry (ESM added in 1.14.0). require("tslib") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "tslib" works alongside it.

Can I require tslib?

Yes. tslib ships a CommonJS entry alongside the native ESM entry. require("tslib") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun.

Does tslib work in Bun?

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

Does tslib ship TypeScript types?

Yes. tslib bundles its own type declarations; no @types package is needed.

Links

Other dual (commonjs + esm) packages

Similar popularity