validateArray

Checks whether a value is an array. This helper uses the isArray type guard internally. Only values for which Array.isArray(value) returns true pass this check.

It never throws and never mutates input. Use it when you need to ensure that a value is an array before applying further structural or element-level validation.

Signature

function validateArray(
  value: unknown,
  field: string
): ValidationResult<unknown[]>

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: unknown[] }: If value is an array.
• { ok: false, field: string, message: string }: If value is not an array.

Behavior

• Uses isArray internally.
• Only arrays pass.
• Objects, functions, Maps, Sets, Dates, and primitives fail.
• Never mutates input.
• Never throws.

Examples

validateArray([1, 2, 3], "items")
// { ok: true, value: [1, 2, 3] }

validateArray({}, "obj")
// { ok: false, field: "obj", message: "Value must be an array" }

validateArray("abc", "str")
// { ok: false, field: "str", message: "Value must be an array" }

Notes

• This validator checks only that the value is an array. It does not validate element types. For that, use higher-level helpers.
• The validator never throws and never mutates input. All error reporting goes through structured ValidationResult objects.