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REDUX & ANGULAR UP & RUNNING
NIR KAUFMAN
AGENDAwhat is redux? how to use redux? where Angular fits in? where to go from here?
WHAT IS REDUX
REDUX IS A DESIGN PATTERNfor managing a complex, ever changing state in a challenging modern single page applications
SINGLE SOURCE OF TRUTHthe state of your whole application is stored within a single store
THE STATE IS READ ONLYthe only way to mutate the state is to emit an action describing what happened
PURE FUNCTIONSto specify how the state is transformed by actions, you write a pure function.
PURE* FUNCTION
ACTION NEXT STATE
* No side-effects
reducer
const currentState = 0; const action = {type: 'INCREASE'}; function reducer(action, currentState){ if(action.type === 'INCREASE') { return currentState + 1; } return currentState; }
const currentState = 0; const action = {type: 'INCREASE'}; function reducer(action, currentState){ if(action.type === 'INCREASE') { return currentState + 1; } return currentState; }
const currentState = 0; const action = {type: 'INCREASE'}; function reducer(action, currentState){ if(action.type === 'INCREASE') { return currentState + 1; } return currentState; }
const currentState = 0; const action = {type: 'INCREASE'}; function reducer(action, currentState){ if(action.type === 'INCREASE') { return currentState + 1; } return currentState; }
const currentState = 0; const action = {type: 'INCREASE'}; function reducer(action, currentState){ if(action.type === 'INCREASE') { return currentState + 1; } return currentState; }
HOW TO USE REDUX
REDUX IS A TINY LIBRARYwhich contains a function for creating a store, and 4 other helpers functions that we can use.
import { createStore } from 'redux'; const store = createStore(reducer);
import { createStore } from 'redux';const store = createStore(reducer);
STORE APIgetState() dispatch(action)subscribe(listener)replaceReducer(reducer)
THE STORE IS SIMPLE TO UNDERSTANDwe can implement a working store in less then 30 lines of code.
function createStore(reducer) { let state = null; const listeners = []; function getState() { return state; } function dispatch(action) { state = reducer(state, action); listeners.forEach(listener => listener()) } function subscribe(listener) { listeners.push(listener); return function () { let index = listeners.indexOf(listener); listeners.splice(index, 1) } } dispatch({ type:’@@INIT' }); return { getState, dispatch, subscribe } }
CONNECTING THE DOTSnow we can dispatch actions and be notified when the state has changed.
dispatch
getStateSTATE
ACTION
STOREUI
UI IS RENDEREDSOMETHING HAPPENEDACTION DISPATCHEDSTATE CHANGEDUI IS RENDEREDSOMETHING HAPPENEDACTION DISPATCHEDSTATE CHANGEDSOMETHING HAPPENED
UNI-DIRECTIONAL DATA FLOW
sync flow
{ LIVE CODING }let’s build a traffic light and see redux in action!
INTERCEPTING THE ACTION FLOWthis is done using middleware which can catch the action before they hit the store.
async flow
STATE
ACTION
STOREUI
Middlewae
{ LIVE CODING }implementing a simple logger as a middleware.
ANGULAR & REDUX
JUST THE VIEWapi as actions logic in middlewares & reducers state inside a store
ANGULAR APP IS A TREE OF COMPONENTSeach component is responsible for rendering a a pert of the state, or dispatching actions.
CONTAINER
COMPONENT COMPONENT
STORE
[properties] (events)
actions
state
BINDING COMPONENTS TO THE STOREit’s straightforward but requires a lot of boilerplate inside the component class.
NPM TO THE RESCUE! FIND AN ADAPTORI will use the ‘angular2-redux-bindings’ for this example
class TodoListComponent { constructor(){ this.unsubscribe = store.subscribe( () => this.renderList ) } ngOnInit(){ this.renderList() } ngOnDestroy(){ this.unsubscribe() } addItem(item){ store.dispatch({ type: 'ADD_ITEM', payload: item }) } renderList(){ this.list = store.getState().list; } }
class TodoListComponent { @MapState('list') private list; @BindActions(addItem) private addItem; }
{ LIVE CODING }let’s build the view layer using Angular2 components
NEXT STEPS
PLAY WITH THE DEMO
https://github.com/nirkaufman/angular-redux-demo
Angular & Redux Workshop
FURTHER READINGREDUX http://redux.js.org/
https://egghead.io/series/getting-started-with-redux
CQRS & EVENT SOURCING https://msdn.microsoft.com/en-us/library/dn568103.aspx
https://msdn.microsoft.com/en-us/library/dn589792.aspx
ANGULAR 2 angular-2-change-detection-explained.html
THANK YOU!
Read our blog:http://blog.500tech.com
Head of Angular Development @ 500Tech
