🟠 Effect vs Selector

For this exercise, you will have a dashboard of activities displaying the name, the main teacher and a list of possible substitutes.

Information

In NgRx, selectors is a very powerful tool that is often misused. You should use them as soon as you need to transform an already existing data in the store.

• You shouldn’t store derived state. This is error-prone because when your data changes, you will have to change it at multiple places => you should have only one place of truth with that data, and every transformation should be done in a selector.

• Inside a component, you shouldn’t transform a selector (using the map operator), and you shouldn’t have to call a selector from a function in your view. The useful logic for preparing data for a component should be done in a selector.

Statement

You will have to refactor this working example of a dashboard of activities.

Constraints

• Only one action should be dispatched from a component (or none, if you can solve the problem with Effect lifecycle hooks).
• Status effect is useless. Using combineLatest should be a red flag. Effects are made for side effects, not for transforming data. That’s a selector’s role.
• Status state might not be useful; it’s only a derived state of existing state.