unique

The array has no duplicate items.

Signature

function unique<T>(by?: (item: T) => unknown, msg?: Message): Action<T[]>

Parameters

Parameter	Type	Description
by	(item: T) => unknown	What to compare by: (u) => u.email. Default — the item itself
msg	Message	Custom error message

Error codes

Code	When	Default message
unique	There are duplicates	Must not contain duplicates

You can change the texts: see Messages & i18n.

Notes

Strings and numbers are compared by value, objects by content.

Example

const Invite = object({
  emails: pipe(array(pipe(string(), email())), unique()),
  members: pipe(array(object({ email: string() })), unique((m) => m.email.toLowerCase())),
});

See also

• array
• minLength