# Is ieee754 ESM-only? Can you require() it?

> ieee754@1.2.1 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Read/write IEEE754 floating point numbers from/to a Buffer or array-like object

Last verified Sep 9, 2026 against ieee754@1.2.1.

ieee754 ships CommonJS only. require("ieee754") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "ieee754" 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("ieee754") 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 ieee754 from "ieee754"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 1.2.1 (Oct 27, 2020)
- Module format: CommonJS
- Last CommonJS version: 1.2.1
- TypeScript types: bundled
- Node engines: not declared
- Weekly downloads: 100.8M
- License: BSD-3-Clause

## Runtime test results for ieee754@1.2.1

Installed and executed on Sep 9, 2026 with require("ieee754") from a CommonJS file and import "ieee754" from an ES module.

| Runtime | require("ieee754") | import "ieee754" |
|---|---|---|
| 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 ieee754

ES modules:

```js
import ieee754 from "ieee754";
```

CommonJS:

```js
const ieee754 = require("ieee754");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (17 versions; the newest 17 shown).

| Versions | Format | First published |
|---|---|---|
| 1.0.0 – 1.2.1 | CommonJS | Dec 28, 2013 |

## Frequently asked

**Is ieee754 ESM-only?**

ieee754@1.2.1 is a CommonJS package. ieee754 ships CommonJS only. require("ieee754") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "ieee754" 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 ieee754 with ES module syntax?**

Yes. import ieee754 from "ieee754" 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 ieee754 work in Bun?**

Yes. import "ieee754" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does ieee754 ship TypeScript types?**

Yes. ieee754 bundles its own type declarations; no @types package is needed.

## Links

- [ieee754 on npm](https://www.npmjs.com/package/ieee754)
- [Source repository](https://github.com/feross/ieee754)
- [HTML version](https://canirequire.com/package/ieee754/)
- [JSON version](https://canirequire.com/package/ieee754.json)

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