Function setClassMetadataAsync

packages/core/src/render3/metadata.ts:60–76

(
  type: Type<any> | AbstractType<any>,
  dependencyLoaderFn: () => Array<Promise<Type<unknown> | AbstractType<unknown>>>,
  metadataSetterFn: (...types: (Type<unknown> | AbstractType<unknown>)[]) => void,
)

 * @param metadataSetterFn Function that forms a scope in which the `setClassMetadata` is invoked
 */
export function setClassMetadataAsync(
  type: Type<any> | AbstractType<any>,
  dependencyLoaderFn: () => Array<Promise<Type<unknown> | AbstractType<unknown>>>,
  metadataSetterFn: (...types: (Type<unknown> | AbstractType<unknown>)[]) => void,
): () => Promise<Array<Type<unknown> | AbstractType<unknown>>> {
  const componentClass = type as any; // cast to `any`, so that we can monkey-patch it
  componentClass[ASYNC_COMPONENT_METADATA_FN] = () =>
    Promise.all(dependencyLoaderFn()).then((dependencies) => {
      metadataSetterFn(...dependencies);
      // Metadata is now set, reset field value to indicate that this component
      // can by used/compiled synchronously.
      componentClass[ASYNC_COMPONENT_METADATA_FN] = ASYNC_METADATA_LOADED;

      return dependencies;
    });
  return componentClass[ASYNC_COMPONENT_METADATA_FN];
}

/**
 * Adds decorator, constructor, and property metadata to a given type via static metadata fields