NgRx is a state management library for Angular applications. It is built on top of the Redux pattern, which is a predictable state container for managing application state in a consistent and scalable way. NgRx extends the Redux pattern to work seamlessly with Angular's components, services, and other features.

The core concepts of NgRx include:

1. Store: The central repository for managing the state of an Angular application. It holds the entire application state, and components can subscribe to changes in the store to receive updates.

2. Actions: These are plain JavaScript objects that describe an event that has occurred in the application. Actions are dispatched to the store to trigger state changes.

3. Reducers: Reducers are pure functions responsible for transforming the current state and an action into a new state. They specify how the application's state changes in response to different actions.

4. Effects: Effects provide a way to manage side effects, such as making API calls, updating the database, or navigating to a different route. Effects listen for specific actions and then perform asynchronous tasks.

5. Selectors: Selectors are functions that retrieve specific pieces of data from the store. They allow components to efficiently access and subscribe to only the relevant parts of the state.

By using NgRx, developers can maintain a clear separation of concerns between components, state management, and side effects. This can lead to more maintainable, testable, and scalable Angular applications.

It's worth noting that while NgRx is a powerful tool for managing state in Angular applications, it also introduces some additional complexity. Developers should carefully consider whether the use of NgRx is appropriate for their project's size and requirements.

Example: I created this example table which uses NgRx, Angular and Material.