Rules of Thumb pt2

When to create actions?

• Anytime we want to interact with the store or API

• No shortcuts

• Use classes for actions

• Use enums for action names

• Export actions types using a union type

• 3 action approach - request, success, failure

• Consider Action Creators

Single action that does everything - Anti Pattern

// Single action that does everything
export class UpdateUsers implements Action {
 readonly type = UserActionTypes.UpdateUsers;
 constructor(public payload: { users: User[] }) {}
}

Sample Action

Related/Nested Data

• Don’t do it

• Complicates reducers

• Easy to mutate store

• Prefer dictionaries vs arrays (NgRx Entity)

Maximize Selectors

Use Selectors to filter/manipulate data from the store

• Supports parameters

• Memoized

• Release memoization

Service With a Subject

• Most projects don’t need NgRx

• Simple pattern

• Works well with container/presenter

• Upgradable to NgRx

Service with a subject basics

• Regular Angular service

• Private member variable of type BehaviorSubject

• Public get prop to access stream

• Service methods update stream

When NOT to use Service with a Subject?

• Application or feature is complex

• Want to track state changes

• Recreate user errors

• Implement advanced logging

Refactor Tour of Heroes to use Service with a subject https://stackblitz.com/github/jessesanders/tour-of-heroes/tree/service-with-subject