Angular Deck#253/282PrevNextQuestion 253 of 282Easy#angular#dependency-injectionWhat is an optional dependency?by TimmoOct 7, 20260 viewsHelpful0SharePractice with AIShow Answer (Space)Self-rating (1 / 2):Needs ReviewMasteredMastered & NextPrevShowAIMasteredNextPrevious (#252/282)Is it mandatory to use injectable on every service class?Next Question (#254/282)What are the types of injector hierarchies?Keyboard shortcuts: ← / → prev/next · Space toggle answer · 1 Mastered · 2 Needs Review.