validateBigInteger

Checks whether a value is a bigint. This helper uses the isBigInteger type guard internally. A bigint is a primitive numeric type used for representing integers of arbitrary size.

It never throws and never mutates input. Use it when you need a strict bigint before normalization or further validation.

Signature

function validateBigInteger(value: unknown, field: string): ValidationResult<bigint>

Parameters

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

Returns

One of:

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

Behavior

• Uses isBigInteger internally.
• Only bigint primitives pass.
• Numbers, strings, booleans, objects, and arrays fail.
• Never throws or mutates input.

Examples

validateBigInteger(1n, "one")
// { ok: true, value: 1n }

validateBigInteger(12345678901234567890n, "large")
// { ok: true, value: 12345678901234567890n }

validateBigInteger(1, "number")
// { ok: false, field: "number", message: "Value must be a bigint" }

validateBigInteger("1", "string")
// { ok: false, field: "string", message: "Value must be a bigint" }

Notes

• This validator does not coerce values. "5" and 5 both fail.
• Because it depends on isBigInteger, boxed bigints (Object(1n)) also fail.
• Suitable for strict validation of IDs, counters, or domains where arbitrary‑precision integers are required.
• The validator never throws and never mutates input. All error reporting goes through structured ValidationResult objects.