Function getInheritedInjectableDef

packages/core/src/di/interface/defs.ts:232–246

(type: any)

 *     scenario if we find the `ɵprov` on an ancestor only.
 */
export function getInheritedInjectableDef<T>(type: any): ɵɵInjectableDeclaration<T> | null {
  // if the ɵprov prop exist but is undefined we still want to return null
  const def = type?.[NG_PROV_DEF] ?? null;

  if (def) {
    ngDevMode &&
      console.warn(
        `DEPRECATED: DI is instantiating a token "${type.name}" that inherits its @Injectable decorator but does not provide one itself.\n` +
          `This will become an error in a future version of Angular. Please add @Injectable() to the "${type.name}" class.`,
      );
    return def;
  } else {
    return null;
  }
}

/**
 * Read the injector def type in a way which is immune to accidentally reading inherited value.