promise

Validates a field using a custom asynchronous function.

Options

Option	Type	Default	Description
promise	(input: ValidatorInput) => Promise<{ valid: boolean, message?: string }>	required	Custom async validation function
message	string	locale default	Custom error message

Playground

Valid values

Value	Notes
Promise resolves { valid: true }	Validation passes

Invalid values

Value	Reason
Promise resolves { valid: false }	Validation fails with default or inline message

Notes

• Empty string ("") always returns valid: true — validators only run on non-empty values. Combine with notEmpty to require a value.
• Same input object as callback: value, elements, options, field.
• For synchronous checks, use callback instead.
• Rejection (thrown error) is treated as invalid.