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Better React state management with Redux | PPTX
Better React
state management
with Redux
Maurice de Beijer
@mauricedb
@react_tutorial
Workshop
goal
 Short recap: what is React?
 Learn the three principals of Redux
 Use the different Redux components
 Unit testing Redux code
 Adding Redux to a React application
 Use Redux middleware
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 Maurice de Beijer
 The Problem Solver
 Microsoft Azure MVP
 Freelance developer/instructor
 Twitter: @mauricedb and @React_Tutorial
 Web: http://www.TheProblemSolver.nl
 E-mail: maurice.de.beijer@gmail.com
3
Follow along
 Git repository: https://github.com/mauricedb/nitflex-redux
 Slides: http://bit.ly/react-redux-workshop
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Type it out
by hand?
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“Typing it drills it into your brain
much better than simply copying
and pasting it.You're forming new
neuron pathways.Those pathways
are going to help you in the future.
Help them out now!”
Prerequisites
Install Node & NPM
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Install
Node.js &
NPM
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Short recap
What is React?
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React
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“React is a JavaScript library for
building user interfaces”
- Facebook -
React
features
 React uses a component based architecture
 Components are written using the JSX syntax
 React likes a one way data flow
 React uses a virtual DOM
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React
Component
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Nitflex
The sample application
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Nitflex
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Main
components
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Application
Login Main Page
Header Billboard Genre List
Genre*
Movie*
Expanded
Movie
Playing
Movie
Stateful
components
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Application
Login Main Page
Header Billboard Genre List
Genre*
Movie*
Expanded
Movie
Playing
Movie
Clone Nitflex
&
NPM install
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Redux
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Redux
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“Redux is a predictable state
container for JavaScript apps”
- Dan Abramov -
Three
principals of
Redux
 Single source of truth
 State is read-only
 Changes are made with pure functions
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Single source
of truth
 The application state is stored in a single location
 Do not scatter the state over lots of components
 A single state location makes it easier to reason
about and debug your application
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State is
read-only
 The state objects are never changed by the
application
 Every state change is the result of an action being
dispatched to the store
 This action describes the intended state change
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Changes
with pure
functions
 Reducers are pure functions that take the current
state and an action as input and return a new state
object
 The previous state object is never modified
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UI versus
App state
 Redux should be used for application state.
 Do not store UI state in Redux!
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Login
example
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Installing
Redux
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ReduxComponents
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Redux
Components
 Actions
 Reducers
 The store
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Login
action
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Login
reducer
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combineReducers
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Unit testing
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Unit test the
action creator
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Unit test the
reducer
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Redux and React
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Redux
and
React
 The NPM react-redux package contains the React
bindings for Redux
 The <Provider> component makes the Redux
store available
 The connect() function connects React components
to the Redux store use in <Provider>
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Create store
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Dispatch
login action
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Get the user
from the store
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Cleanup
 app-container.jsx
 Remove user and loginAsUser()
 app-presentation.jsx
 Remove loginAsUser()
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Redux Middleware
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Redux
Middleware
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“Redux middleware provides a
third-party extension point between
dispatching an action, and the
moment it reaches the reducer”
- Dan Abramov -
Installing
redux-thunk
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Redux-Thunk
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What is a
Thunk?
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“A thunk is a subroutine that is
created, often automatically, to
assist a call to another subroutine”
-Wikipedia -
Configure
Thunk
Middleware
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Update
the
Actions
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Add movies
reducer
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Update the
reducers
index.js
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Extract
movies
from
store
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Cleanup
 app-container.jsx
 Remove allMovies and passing movies to
AppPresentation
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Redux DevTools
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Redux
DevTools
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Redux
DevTools
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Remember the user
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Remember
the user
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Playing and
stopping movies
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Add actions
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Update
reducer
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Start
playing
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Retrieve the
playing
movie from
the store in
app-
presentation
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Retrieve the
playing
movie from
the store in
playing-
movie
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Cleanup
 app-container.jsx
 main-page/index.jsx
 genre-list.jsx
 genre-row.jsx
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Filtering movies
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Filtering
movies
 The list of filtered movies are derived from state
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Add action
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Reducer
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Filter-
movies.jsx
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App-
presentation.
jsx
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Cleanup
 Header.jsx
 Remove filterMovies
 Main-page/index.jsx
 Remove filterMovies
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Remove
app-container
The AppContainer is no longer needed.
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Index.js
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Connect only to
required movie data
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Main-page
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Genre-list
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Billboard
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App-
presentation
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Bonus
Exercises
 Extract updating localStorage from user reducer
and do this with middleware
 The user is passed from AppPresentation =>
MainPage => Header
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MauricedeBeijer
@mauricedb
maurice.de.beijer
@gmail.com
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Better React state management with Redux