Function: optional()

optional<K>(key): OptionalDependency<K>

Defined in: src/dependencies.ts:28

Marks a dependency as optional: the factory receives the service when it is registered, and undefined otherwise.

Type Parameters

K

K extends ServiceKey

Parameters

key

K

Returns

OptionalDependency<K>

Example

container.addSingleton(
  'mailer',
  (transport) => new Mailer(transport ?? consoleTransport),
  [optional('transport')],
);