canirequire › CommonJS › is-number
Is is-number ESM-only? Can you require() it?
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. JSON
CommonJS CommonJS — require() works on every Node.js version
is-number ships CommonJS only. require("is-number") works everywhere. 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.
Does is-number@7.0.0 actually load? Runtime test results
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 | ✓ works | ✓ works |
How to import is-number
ES modules (import)
import isNumber from "is-number";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 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 everywhere. 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 on Sep 9, 2026.
Does is-number ship TypeScript types?
Not bundled. Install the community types with "npm install -D @types/is-number".
Links
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