Numeric Type Guards

Runtime type guards to validate numeric values.

Imports

import { isInteger, isPositiveInteger, isNumericString } from 'toolbox-x/guards';

isInteger

Validates if a value is an integer.

Signature

isInteger(value: unknown): value is number

Examples

isPositiveInteger

Validates if a value is a positive integer.

Signature

isPositiveInteger(value: unknown): value is number

Examples

isNumericString

Validates whether a value is a string that fully represents a finite number.

Signature

isNumericString(value: unknown): value is `${number}`

Description

This function checks:

• ✅ Integers: '42', '-15'
• ✅ Decimals: '3.14', '0.5', '-.99'
• ✅ Scientific notation: '1e5', '-2.5e-3'
• ✅ Strings with leading/trailing whitespace (they are trimmed)

It excludes any string that would result in:

• ❌ NaN (e.g. 'abc', '', '42px')
• ❌ Infinity, -Infinity
• ❌ Hexadecimal numbers (e.g. '0xFF')
• ❌ Strings that only partially parse into a number

Examples