feat(): add topic about using component state from ngrx

content/ngrx/use-component-state.md

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+---
+title: use component state
+---
+
+# Problem
+
+Sometimes you'll need to handle component state, but it shouldn't be added to the global state because:
+1) It'd bloat the global state
+2) Specific state or UI state should belong to the component (like showing a previously hidden form when editing an item, this is something that should belong to the component state and not the global one)
+
+# Solution
+
+You can use NgRx component store package [@ngrx/component-store](https://ngrx.io/guide/component-store) which allows to have a component store for all the state requirements of the specific component you have.
+
+**Key Concepts from the NgRx docs:**
+
+- Local state has to be initialized, but it can be done lazily.
+- Local state is typically tied to the life-cycle of a particular component and is cleaned up when that component is destroyed.
+- Users of ComponentStore can update the state through setState or updater, either imperatively or by providing an Observable.
+- Users of ComponentStore can read the state through select or a top-level state$. Selectors are very performant.
+- Users of ComponentStore may start side-effects with effect, both sync and async, and feed the data both imperatively or reactively.