Suggest an editImprove this articleRefine the answer for “What does the term "single source of truth" mean?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**"Single source of truth"** is a principle where certain data is stored in only one place, and every part of the application reads from that place. **Key point:** a single source of truth is the one place where the real data lives, and everything else just looks there.Shown above the full answer for quick recall.Answer (EN)Image**"Single source of truth"** is a principle where **certain data is stored in only one place**, and every part of the application reads from exactly that place. --- ### Why it's needed: - So there are **no discrepancies** between different copies of the same data. - So that **all updates are centralized** and controlled. - To make the application easier to debug and maintain. --- ### Example: If the user is stored in a component, in a service, and in local storage, sooner or later you will forget to update one of them. But if the **entire user object is stored only in** `AuthService.user$`, and every component reads from there alone, everything stays under control. --- ### In Angular: - A `BehaviorSubject` in a service is a common "single source of truth" - The Store in NgRx is a global, formal single source of truth for the whole application --- **Conclusion:** A single source of truth is **the one place where the real data lives**, and everything else just looks there. That means fewer bugs and more predictability.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.