Function MapUnique

MapUnique<Value, Projection>(projection, options?): PropertyDecorator
Checks if the given value is a Map without duplicates with regard to the given projection.

Example
```
// Ensure the map does not include duplicate users.
@MapUnique<User>(user => user.id)
usersByEmail: Map<string, User>
```
Type Parameters
- Value = unknown
  The type of the map's values.
- Projection = Value
  The type returned by projection.
Parameters
- projection: ((item) => Projection)
  The function mapping each map entry to the value that is used for the uniqueness check.
  - - (item): Projection
    - Parameters
      item: Value
      Returns Projection
- Optional options: ValidationOptions
  Generic class-validator options.
Returns PropertyDecorator
- Defined in src/map/map-unique/map-unique.decorator.ts:26