CollectionItemValidatorCallback

API / CollectionItemValidatorCallback<TValidatable, TItem> type

Represents a collection bound validator callback.

type CollectionItemValidatorCallback<TValidatable extends IReadOnlyValidatable, TItem> = (validatable: TValidatable, item: TItem, collection: readonly TItem[]) => string | undefined

Template Parameters

• TValidatable: the type of validatable objects to validate. Must implement IReadOnlyValidatable.
• TItem: the type of items the collection contains.

Parameters

• validatable: TValidatable, the object being validated.
• item: TItem, the item from which the validatable has been selected.
• collection: readonly Array<TItem>, the collection to which the item belongs.

Returns: String or undefined

Returns an error message (or translation key) providing information as to why the validatable is invalid.