provideTokenOptional<T extends Object> method

@nonVirtual T? provideTokenOptional<T extends Object>(OpaqueToken<T> token)

Finds and returns an object instance provided for a token.

Unlike provideToken, null is returned if a provider is not found.

NOTE: The List<T> returned by dependency injection is not guaranteed to be identical across invocations - that is, a new List instance is created every time a provider backed by a MultiToken is used:

const usPresidents = MultiToken<String>('usPresidents');

void example(Injector i) {
  final a = i.provideToken(usPresidents);
  final b = i.provideToken(usPresidents);
  print(identical(a, b)); // false
}

Implementation

@nonVirtual
T? provideTokenOptional<T extends Object>(OpaqueToken<T> token) {
  return unsafeCast(get(token, null));
}