fix: Improve type safety and API consistency in ArticlesService#327

xingarr wants to merge 2 commits intorealworld-apps:mainrealworld-apps/angular-realworld-example-app:mainfrom

xingarr:fix/some-types-safety-and-api-consistencyxingarr/angular-realworld-example-app:fix/some-types-safety-and-api-consistencyCopy head branch name to clipboard