is-number-modern

Tiny, zero-dependency function to check if a value is a number or a numeric string. ESM + CJS dual build, TypeScript types included.

Install

npm install is-number-modern

Usage

import { isNumberModern } from 'is-number-modern';

isNumberModern(42);          // true
isNumberModern(new Number(1)); // true
isNumberModern('42');        // true
isNumberModern('-3.14');     // true
isNumberModern(Infinity);    // true
isNumberModern(NaN);         // false
isNumberModern('');          // false
isNumberModern('  ');        // false
isNumberModern('foo');       // false
isNumberModern([]);          // false

CommonJS:

const { isNumberModern } = require('is-number-modern');

Behavior

• Accepts: number literals, Number objects, numeric strings (e.g. "42"), floats, negatives, Infinity.
• Rejects: NaN, symbols, arrays, objects, booleans, empty strings, whitespace-only strings, non-numeric strings.
• Returns true only if the value can be safely converted to a number; NaN and non-numeric inputs return false.

API

export function isNumberModern(value: unknown): boolean;

Tree-shaking

• Named exports and "sideEffects": false enable aggressive tree-shaking.

Development

npm run build
npm test
npm run typecheck