Download - Corso su ReactJS
A React JourneyA tour of the latest trends in the React ecosystem
JS Frontend Developer at LinkMe Srl
Twitter: @_denb
In love with React and Javascript in general.I’m a 7-month-old dad
Daniele Bertella
JS Frontend Jr Developer at LinkMe Srl
Twitter: @paolorovella
In love with React and sushi, i’m an incurable tv shows binge watcher
Paolo Rovella
ReactReact is a JavaScript library for creating user interfaces
https://facebook.github.io/react
ReactMain concepts
Just the UI
React is only concerned about rendering UI
Virtual DOM
React uses a Virtual DOM Diff implementation for ultra-high performance
Data Flow
React introduces one-way reactive data flow
Components
ReactA basic component
ReactJSX
JSX is a XML-like syntax extension to ECMAScript
https://facebook.github.io/jsx/
ReactComponent Specs
getInitialState()Invoked once before the component is
mounted. The return value will be used as the initial value of this.state.
getDefaultProps()Invoked once, before any instances are created. The return value will be used
as the initial value of this.props.
propTypesThe propTypes object allows you to validate props being
passed to your components
ReactProps
Input data that is passed into the component and can be accessed
via this.props
The propTypes object allows you to validate props being passed to
your components
PropTypes validation providedhttps://facebook.github.io/react/docs/reusable-components.html#prop-validation
ReactState
Internal state dataA component can maintain internal state data (accessed via this.state)
Re-render on state changesWhen a component's state data
changes, the rendered markup will be updated by re-invoking render()
ReactComponent Lifecycles
Various methods are executed at specific points in a component's
lifecycle.
https://facebook.github.io/react/docs/component-specs.html#lifecycle-methods
ReactMixins
Share common functionality
Break repetitive tasks out into standalone pieces optionally included within one or more
components.
ReactECMAScript 6 (ES6) is the upcoming sixth major release of
the ECMAScript language specification.
ES6 support is different among browsers(https://kangax.github.io/compat-table/es6/)
You can use ES6 today thanks to transpilers like Babel
ECMAScript 6 (ES6)
BabelJavascript compiler
Transpile ES6/ES7 in ES5
(Classes / Destructuring / Arrow functions / Spread operator ...)
http://babeljs.io
BabelLearn ES6
http://babeljs.io/docs/learn-es2015/
ReactES5 to ES6 ClassesECMAScript 6 equivalents in ES5 by @addyosmani
https://github.com/addyosmani/es6-equivalents-in-es5
ReactES6 Destructuring
ES6 Arrow function
Expression that make it possible to extract data from arrays or object into dinstinct variables
Shorter syntax compared to function expressions and binds the “this” value (not its own this). They are always anonymous
ReactES6 Object Spread operator
ES6 Decorators
Copy properties from one object to another. The specification order is important
Syntactic sugar which lets you annotate and modify classes at design time
ReactStateless Functional Components
Kill boilerplate code
Dumb and predictable component
No state, no component lifecycles
ReactHigh Order Components
Reuse other components functionalities
Reduce duplication of code
Mixins Are Dead. Long Live Composition
https://medium.com/@dan_abramov/mixins-are-dead-long-live-higher-order-components-94a0d2f9e750
ReactHigh Order Components
Thanks @cef62 (Matteo Ronchi)https://speakerdeck.com/cef62/higher-order-
components-in-react-at-voxxed-days-ticino-2016
ReactRouting (react-router) https://github.com/reactjs/react-router
State management
ReduxBy Dan Abramov (@dan_abramov)
https://github.com/reactjs/redux
Predictable state container for JavaScript apps.
Three principles
- Single source of truth- State is read only- Changes are made with pure functions
ReduxApp state
App state described as a plain object
This object is like a “model” except that there are no setters
ReduxActions
The only way to mutate the state is to emit an action, an object describing what happened
ReduxReducers
A function that takes previous state and action as arguments, and
returns the next state of the app
Split reducers in smaller functions managing parts of the state
ReduxReducers
A reducer that manage the complete statecan call other small reducers
ReduxAPI
combineReducers Combine different
reducers in one
createStoreTwo arguments, combined
reducers and persisted state (optional)
Reduxsubscribe
Adds a change listener. Called any time an action is dispatched, and some part of the state
tree may potentially have changed
getStateReturns an object with the current state tree
of your application
dispatch Dispatches an action. This is the only way to
trigger a state change
Store
Reduxreact-reduxPresentational and Container Components
Provider
makes the store available to all container components in the app
only need to use it once when you render the root component
Reduxreact-redux
Reduxreact-redux
connect(params)(Component)
connects a React component to a Redux store.
returns a new, connected component class
Reduxreact-redux
mapStateToProps
a function that tell how to transform the current Redux store state into the props
you want to pass.
mapDispatchToProps
a function that receives dispatch() method and returns a callback props.
ReduxMiddlewares
Suggested way to extend Redux with custom functionality
They are called after an action is dispatched and before it reaches the
reducer
Multiple middlewares can be combined together
Redux Saga middleware let you create Sagas, which are generators responsible for orchestrating complex/asynchronous operations, to gather all your side effects logic in a central place
Reduxredux-thunkhttps://github.com/gaearon/redux-thunk
Middlewares
Redux Thunk middleware allows you to write action creators that return a function instead of an action
The thunk can be used to delay the dispatch of an action, or to dispatch only if a certain condition is met
redux-sagahttps://github.com/yelouafi/redux-saga
MobXBy Michel Weststrate (@mweststrate)
https://github.com/mobxjs/mobx
MobX is a library that makes state management simple and scalable by transparently applying functional reactive programming
Functional reactive programming
Functional reactive programming is programming with asynchronous data streams which you can listen to and react accordingly
The introduction to Reactive Programming you've been missing
https://gist.github.com/staltz/868e7e9bc2a7b8c1f754
MobXStore (observable/computed)
@observable stateobservable capabilities to objects, arrays and class instances annotating properties
with the @observable decorator
@computedvalues that will be derived automatically
when relevant data is modified
@actionaction is anything that modify
the state and is always triggered by some event (DOM events,
websockets etc)
MobXStore (action)
MobX@observer
observer function / decorator is used to turn ReactJS components into
reactive components.
In this component store can be passed as a prop
mobx-react
MobXFlow
API overview
https://mobxjs.github.io/mobx/refguide/api.html
In-depth explanation of MobX
https://medium.com/@mweststrate/becoming-fully-reactive-an-in-depth-
explanation-of-mobservable-55995262a254
Testing
EnzymeBy Airbnb (@airbnb)
https://github.com/airbnb/enzyme
Enzyme is a JavaScript testing utility for React.
React components are easy to test because they simply return a description for what UI of the component should look like.
This “description” is the “Virtual DOM” and is a tree-like data structure
Enzyme
Shallow is the recommended mode to start with since it does a better job of isolating your
tests to just a single component
Shallow rendering
Enzyme exports three different “modes” to render and test components: shallow, mount, and render.
EnzymeEnzyme Selectors can find nodes by 4 categories:
CSS selectors
React component constructor
React component display name
Object properties
Enzyme selectors
EnzymeConcise and elegant way of simulating user events, one of the trickier aspects
of UI testing.
Just pass the name of the event you want to simulate, along with any
required data
Event simulations
WebpackModule bundler
Loaders
Plugins
http://webpack.github.io
WebpackModule bundler
WebpackLoaders
TestA regular expression that matches the file extensions that
should run through this loader (required)
Include / ExcludeSet which folders and files the loader should add or ignore
LoaderThe name of the loader (required)
Query
Used to pass Additional options to the loader
WebpackPlugins
Tutorial
http://www.pro-react.com/materials/appendixA
Plugins have the ability to inject themselves into the build process to
introduce custom behaviors.
They do not operate like loaders on individual source files: they influence
the build process as a whole.
CSS in JShttps://github.com/MicheleBertoli/css-in-js
React: CSS in JS techniques comparison
CSS ModulesConcept of using a module bundler, such
as webpack, to load CSS scoped to a particular document
https://github.com/css-modules/css-modules
CSS ModulesWebpack configurationhttps://github.com/css-modules/webpack-demo
CSS ModulesHow to use
CSS ModulesCompositionhttps://github.com/css-modules/webpack-
demo/tree/master/src/components/3-ClassComposition
CSS ModulesComposition
Atomic CSS Moduleshttps://medium.com/yplan-eng/atomic-css-modules-cb44d5993b27
https://speakerdeck.com/michelebertoli/css-in-js
One more thing...
https://speakerdeck.com/paolorovella/react-native