redux data flow with angular 2

REDUX DATA FLOW WITH

ANGULAR 2

Gil Fink

CEO and Senior Consultant, sparXys

@gilfink

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Then you make a small change…

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

Agenda • The Redux pattern

• Combining Redux and Angular 2

• ng2-redux library in a nutshell

Known SPA Complexity Solutions

• Command Query Responsibility Segregation (CQRS)

• Event Sourcing

• Flux

• And more

Redux • Design pattern based on Flux

o But it’s not Flux!

• Predictable state container for JavaScript apps

Redux Principles 1. Single source of truth

Single Source of Truth • The application state is stored in an object tree

within a single store

let state = store.getState();

Redux Principles 1. Single source of truth

2. State is read-only

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 });

Redux Principles 1. Single source of truth

2. State is read-only

3. Changes are made with pure functions

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; } }

Let’s drill down

Redux Data Flow

Action Creators

View

Reducers Store

interaction (click, mouse etc.)

dispatch(action) (previous state, action)

(new state) (current state)

Redux Data Flow – Cont.

Action Creators

View

Reducers Store

interaction (click, mouse etc.)

dispatch(action) (previous state, action)

(new state) (current state)

Outside Action (push, Ajax

callback and etc.)

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)

Demo Redux in action

What about Angular?

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

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

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); } }

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}); } }

Demo Simple Redux + Angular 2 app

Summary • Redux

o Is a data flow design pattern

o Reduces complexity when building big SPAs

o Can be applied in Angular apps

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

Thank You!