canirequire

canirequire › ESM-only › onetime

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

Ensure a function is only called once

Last verified Sep 9, 2026 against onetime@8.0.0. JSON

ESM-only ESM-only since 6.0.0 — last CommonJS version is 5.1.2

onetime dropped its CommonJS build in 6.0.0 (April 2021). The last version you can require() on every Node.js version, including 18 and older, is 5.1.2, published Aug 9, 2020.

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

onetime@8.0.0 declares engines ">=22", so Node.js 18, 20 are outside its supported range regardless of module format.

Latest
8.0.0 (Feb 2, 2026)
Module format
ESM-only
Last CommonJS version
5.1.2
ESM-only since
6.0.0 (Apr 8, 2021)
TypeScript types
Bundled
Node engines
>=22
Weekly downloads
162.3M
License
MIT

Does onetime@8.0.0 actually load? Runtime test results

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

Runtimerequire("onetime")import "onetime"
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 onetime

ES modules (import)

import onetime from "onetime";

CommonJS (require)

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

// Any Node.js version:
const onetime = await import("onetime");

// Or pin the last CommonJS release:
// npm install onetime@5.1.2

Module format by version

Derived from the type, main and exports fields of every stable release on npm (15 versions; the newest 15 shown).

VersionsFormatFirst published
6.0.0 – 8.0.0ESM-onlyApr 8, 2021
0.1.0 – 5.1.2CommonJSDec 13, 2013

Frequently asked

Is onetime ESM-only?

onetime@8.0.0 is ESM-only. onetime dropped its CommonJS build in 6.0.0 (April 2021). The last version you can require() on every Node.js version, including 18 and older, is 5.1.2, published Aug 9, 2020.

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

5.1.2 is the last version of onetime with a CommonJS build. Install it with "npm install onetime@5.1.2". Every version from 6.0.0 on is ESM-only.

How do I use onetime from a CommonJS file?

Use a dynamic import: const mod = await import("onetime"). On Node.js 20.19+, 22.12+ and newer, a plain require("onetime") also works for ESM packages that do not use top-level await. Alternatively pin onetime@5.1.2.

Does onetime work in Bun?

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

Does onetime ship TypeScript types?

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

Links

Other esm-only packages

Similar popularity