This document discusses combining Redux and Angular 2 for managing application state. It introduces Redux as a pattern based on Flux that uses a single state container. Key principles are a single source of truth for state, immutable state changes via pure functions, and a unidirectional data flow from views to actions to reducers to stores. The ng2-redux library makes it easy to use Redux in Angular 2 by providing store injection and selectors to observe state. Redux can reduce complexity for large single-page apps and is applicable to Angular.

1. REDUX DATA FLOW WITH
ANGULAR 2
Gil Fink
CEO and Senior Consultant, sparXys
@gilfink

2. SPAs Are Complex

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6. Then you make a small
change…

8. About Me
• sparXys CEO and senior consultant
• Microsoft MVP in the last 8 years
• Pro Single Page Application Development (Apress)
co-author
• 4 Microsoft Official Courses (MOCs) co-author
• GDG Rishon and AngularUP co-organizer

9. Agenda
• The Redux pattern
• Combining Redux and Angular 2
• ng2-redux library in a nutshell

10. Known SPA Complexity
Solutions
• Command Query Responsibility Segregation (CQRS)
• Event Sourcing
• Flux
• And more

11. Redux
• Design pattern based on Flux
o But it’s not Flux!
• Predictable state container for JavaScript apps

12. Redux Principles
1. Single source of truth

13. Single Source of Truth
• The application state is stored in an object tree
within a single store
let state = store.getState();

14. Redux Principles
1. Single source of truth
2. State is read-only

15. State is Read-Only
• The only way to mutate the state is to emit an
action describing what happened
store.dispatch({
type: 'ADD_GROCERY_ITEM',
item: { productToBuy: 'Milk' }
});
store.dispatch({
type: 'REMOVE_GROCERY_ITEM',
index: 3
});

16. Redux Principles
1. Single source of truth
2. State is read-only
3. Changes are made with pure functions

17. Changes Are Made with
Pure Functions
• To specify how the state is transformed by actions,
you write a pure function
o Called reducer
function groceryItemReducer(state, action) {
switch (action.type) {
case 'ADD_GROCERY_ITEM':
return object.assign({}, state, {
groceryItems: [
action.item,
…state.groceryItems
]
};
default:
return state;
}
}

18. Let’s drill down

19. Redux Data Flow
Action
Creators
View
ReducersStore
interaction (click, mouse etc.)
dispatch(action) (previous state, action)
(new state)
(current state)

20. Redux Data Flow – Cont.
Action
Creators
View
ReducersStore
interaction (click, mouse etc.)
dispatch(action) (previous state, action)
(new state)
(current state)
Outside Action
(push, Ajax
callback and etc.)

21. Redux Library API
• Redux is a small and compact library:
o createStore(reducer)
o combineReducers(reducers)
o applyMiddleware(middlewares)
o compose(functions)
o bindActionCreators(creators, dispatch)
o Store API:
• store.dispatch(action)
• store.getState()
• store.subscribe(listener)

22. Demo
Redux in action

23. What about Angular?

24. Angular and Redux
• Redux can be applied in Angular oriented
applications
o It’s a data flow pattern
• Popular Angular 2 & Redux libraries:
o ngrx/store
o ng2-redux

25. ng2-redux
https://github.com/angular-redux/ng2-redux

26. ng2-redux - Setup
• Add the module
• Create the store and provide it in the main module
import { NgReduxModule, NgRedux } from 'ng2-redux';
@NgModule({
imports: [ /* ... */, NgReduxModule ]
})
class AppModule {
constructor(ngRedux: NgRedux<IAppState>) {
ngRedux.provideStore(store);
}
}

27. ng2-redux - Usage
• Use the @select decorator and dispatch function:
class App {
@select() counter: Observable<number>;
constructor(private ngRedux: NgRedux<IAppState>) {}
increment() {
this.ngRedux.dispatch({ type: INCREMENT});
}
}

28. Demo
Simple Redux + Angular 2 app

29. Summary
• Redux
o Is a data flow design pattern
o Reduces complexity when building big SPAs
o Can be applied in Angular apps

30. Resources
• Redux:
https://github.com/reactjs/redux
• ng2-redux:
https://github.com/angular-redux/ng2-redux
• ngrx/store:
https://github.com/ngrx/store
• My Blog – http://www.gilfink.net
• Follow me on Twitter – @gilfink

31. Thank You!