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

> is-number@7.0.0 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Returns true if a number or string value is a finite number. Useful for regex matches, parsing, user input, etc.

Last verified Sep 9, 2026 against is-number@7.0.0.

is-number ships CommonJS only. require("is-number") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=0.12.0. import "is-number" 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("is-number") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=0.12.0.
2. From ES modules use the default import: import isNumber from "is-number"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: npm install -D @types/is-number

## Facts

- Latest: 7.0.0 (Jul 4, 2018)
- Module format: CommonJS
- Last CommonJS version: 7.0.0
- TypeScript types: @types/is-number
- Node engines: >=0.12.0
- Weekly downloads: 154.7M
- License: MIT

## Runtime test results for is-number@7.0.0

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

| Runtime | require("is-number") | import "is-number" |
|---|---|---|
| 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 is-number

ES modules:

```js
import isNumber from "is-number";
```

CommonJS:

```js
const isNumber = require("is-number");
```

## Module format by version

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

| Versions | Format | First published |
|---|---|---|
| 0.1.0 – 7.0.0 | CommonJS | Sep 22, 2014 |

## Frequently asked

**Is is-number ESM-only?**

is-number@7.0.0 is a CommonJS package. is-number ships CommonJS only. require("is-number") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=0.12.0. import "is-number" 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 is-number with ES module syntax?**

Yes. import isNumber from "is-number" 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 is-number work in Bun?**

Yes. import "is-number" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does is-number ship TypeScript types?**

Not bundled. Install the community types with "npm install -D @types/is-number".

## Links

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

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