isNumber

Problem

You need to guard numeric values from generic inputs — for example validating config values or discriminating a union type.

Solution

Use isNumber(value) to narrow to number.

import { isNumber } from '@vielzeug/arsenal';

isNumber(42); // true
isNumber(NaN); // true — NaN is typeof 'number'
isNumber('42'); // false

Pitfalls

• NaN passes isNumber — add && !isNaN(value) if you need to exclude it.

Related

• isString
• isPrimitive