validateNumber

Checks whether a value is a primitive number. This helper performs a strict number check using isNumber. It accepts all number primitives, including NaN, Infinity, and -Infinity.

It never throws and never mutates input. Use it when you need to confirm a value is a number before normalization or further validation.

Signature:

function validateNumber(value: unknown, field: string): ValidationResult<number>

Parameters

Name	Type	Description
value	unknown	The value to validate.
field	string	The name of the field being validated, used in error reporting.

Returns

ValidationResult<number> — One of:

• { ok: true, value: number }: If value is a primitive number.
• { ok: false, field: string, message: string }: If value is not a number.

Behavior

• Uses isNumber internally.
• All primitive numbers pass, including NaN, Infinity, -Infinity.
• Non-number values fail.
• Never throws or mutates input.

Examples

validateNumber(0, "zero")
// { ok: true, value: 0 }

validateNumber(-123, "negative")
// { ok: true, value: -123 }

validateNumber(NaN, "nan")
// { ok: true, value: NaN }

validateNumber(Infinity, "inf")
// { ok: true, value: Infinity }

validateNumber("123", "string")
// { ok: false, field: "string", message: "Value must be a number" }

validateNumber(new Number(123), "boxed")
// { ok: false, field: "boxed", message: "Value must be a number" }

Notes

• Use validateNumber when you require a strict primitive number.
• Combine with normalizeNumber or other normalizers if needed.
• NaN and Infinite values are allowed. Use additional validators if you need finite numbers only.