React Native

Native App Development for Web Developers

Nader Dabit

@dabit3 on Twitter & Github

About Me

  • Software developer by trade
  • Now a full time consultant and trainer
  • Originally a web developer, now doing both web and mobile development
  • Transitioned from Angular > React + React Native in early 2015
  • Founder of React Native Training
  • Author of React Native in Action from Manning Publications
  • Host of React Native Radio on Devchat.tv
  • Open source contributor to React Native and various React Native projects

What is React Native?

Framework for building Native Mobile Apps using JavaScript

  • Built on top of React
  • Use React Native to build cross platform mobile applications
  • Open sourced and maintained by Facebook
  • Apps written in JavaScript
  • Learn once, write anywhere
  • 80%-95% code reuse
  • Compiles to real native mobile applications 
  • Uses the same fundamental UI building blocks as real native apps under the hood

React Native vs HTML

<div>
  <p>Hello World</p>
</div>
<View>
  <Text>Hello World</Text>
</View>

HTML

React Native

React Native vs HTML

HTML | React Native

<div> == <View>
<p> || <span> == <Text>
<button> == <TouchableHighlight>
<img /> == <Image />
<input /> == <TextInput />

React Native vs React

import React from "react"

class SomeComponent extends React.Component {
  render () {
    return (
      <div>
        <p>Hello World</p>
      </div>
    )
  }
}

React

React Native vs React

import React from "react"
import { View, Text } from "react-native"

class SomeComponent extends React.Component {
  render () {
    return (
      <View>
        <Text>Hello World</Text>
      </View>
    )
  }
}

React Native

React Native Elements

import { Button, SocialIcon } from "react-native-elements"

<Button
  title="Button" />

<SocialIcon
  type="facebook" />

React Native vs Hybrid

Pros

  • Project momentum
  • React ecosystem / Redux / one way data flow / Mobx
  • Better user experience - apps feel much better and smoother
  • No longer dealing with browser apis
  • Great developer experience
  • Hot / live reloading
  • Open Source
  • Core contributors of React Native are using it in their own production apps and in their companies
  • Fun to build once you learn the framework
  • Will be able to build for desktop, web, + other platforms
  • Continuous deployment easy to integrate (Code Push and similar)

React Native vs Hybrid

Cons

  • Still new - 24 months iOS / 18 months Android
  • Fairly Unstable - New versions every 2 weeks, some with breaking changes
  • Another technology that you have to learn (React), while Cordova can be picked up quickly by anyone who knows HTML + JavaScript.
  • Unfamiliar development environments and platforms (xCode, Android IDE)
  • Styling inconsistencies with CSS
  • Not yet quite to feature parity with Cordova

Is React Native Production Ready?

  • Facebook Groups
  • Facebook Ads Manager
  • Facebook News Feed
  • Instagram
  • Tesla
  • Wix
  • WalMart
  • Airbnb
  • Delivery.com
  • Amazon.com
  • Microsoft

Current Platforms

Can currently target Android, iOS and Windows

In development to target MacOS, Web, Tizen

Future / Developing Platforms

Compiles this:

React Native Web

<div>
  <span>Hello World</span>
</Div>

To this:

<View>
   <Text>Hello World</Text>
</View>

Fundamental changes in the way future engineered teams are designed and organized.

What this means

Single Team => 2 - 5 Platforms

  • Organized by technology
  • iOS, Android, Web, Desktop teams
  • Expensive to build and maintain across platforms
  • Inconsistent APIs
  • Difficult to test across platforms
  • Virtually zero code reuse
  • Multiple languages, frameworks, and APIs

Traditional Engineering Teams

  • Organized by feature ownership
  • Single team working on Mobile, Web, and Desktop
  • Much less expensive to build and maintain applications across platforms
  • Consistent APIs
  • Less context switching
  • Large increase in code reuse
  • Single or smaller number of languages
  • Smaller number of frameworks
  • Possible consulting with native developers for complex feature implementations.
  • Nodejs backend ++

Engineering Team of the Future

Cross stack engineering is an opportunity that is blossoming with React Native

- James Ide, Engineer at Expo

Team × Technology React Conf 2016

  • Faster development time
  • Consistent apis
  • Can build for Web, Desktop, and Mobile
  • Was organized by platform, now by feature
  • Consistent user experience across platforms
  • Those familiar with native platforms will be especially valuable
  • Development is less expensive in terms of time and money
  • Cross Stack engineers more valuable, resulting in higher pay

Birth of the Cross Stack Developer

Growing opportunity in this space

Because Native development is becoming more and more expensive, engineers who can deliver applications across platforms and stacks will become extremely valuable and in demand.

Coming to React Native from the web

  1. Dev environments / IDEs
  2. Application UI
  3. Routing
  4. Styling inconsistencies vs CSS
  5. Publishing apps to Play and App Store
  6. Bridging native code (advanced dev)

Main stumbling blocks

Xcode (iOS)

Xcode (iOS)

Coming to React Native from the web

Routing / Navigation

  • Different paradigm than web routing
  • Navigation flows are hard to reproduce
  • Navigation UX is different each platform (managed by some navigation frameworks)

Routing - React

Coming to React Native from the web

import {
  BrowserRouter as Router,
  Route,
  Switch,
  Redirect
} from 'react-router-dom'

const App = () => (
  <Router>
    <ul>
      <li><Link to="/">Home</Link></li>
      <li><Link to="/about">About</Link></li>
      <li><Link to="/topics">Topics</Link></li>
    </ul>
    <Switch>
      <Route exactly pattern="/" component={Home} />
      <Route pattern="/about" component={About} />
      <Route pattern="/topics" component={Topics} />
      <Route component={NoMatch}/>
    </Switch>
  </Router>
)

Coming to React Native from the web

Routing / Navigation - Angular 2

const appRoutes: Routes = [
  { path: 'home', component: Home },
]

@NgModule({
  imports: [
    RouterModule.forRoot(appRoutes)
    // other imports here
  ],
  ...
})
// HTML

<h1>Angular Router</h1>
<nav>
  <a routerLink="/" routerLinkActive="active">Home</a>
  <a routerLink="/about" routerLinkActive="active">About</a>
</nav>

<router-outlet></router-outlet>

Coming to React Native from the web

Routing / Navigation - Vue

const NotFound = { template: '<p>Page not found</p>' }
const Home = { template: '<p>home page</p>' }
const About = { template: '<p>about page</p>' }
const routes = {
  '/': Home,
  '/about': About
}
new Vue({
  el: '#app',
  data: {
    currentRoute: window.location.pathname
  },
  computed: {
    ViewComponent () {
      return routes[this.currentRoute] || NotFound
    }
  },
  render (h) { return h(this.ViewComponent) }
})
import React from 'react';
import {
  Text,
  View,
  Button,
} from 'react-native';
import { StackNavigator } from 'react-navigation';
import AboutScreen from './AboutScreen'

class App extends React.Component {
  static navigationOptions = {
    title: 'Welcome',
  };
  render() {
    const { navigate } = this.props.navigation;
    return (
      <View>
        <Text>Hello!!</Text>
        <Button
          onPress={() => navigate('About')}
          title="Chat with Lucy"
        />
      </View>;
  }
}

const SimpleApp = StackNavigator({
  Home: { screen: HomeScreen },
  About: { screen: AboutScreen },
});

export default SimpleApp

Routing / Navigation - React-Navigation

Coming to React Native from the web

Navigation - Getting Started

Explore different router Apis, choose one that makes sense to you

  1. react-navigation - React Native Community
  2. react-native-navigation - Wix

Coming to React Native from the web

Styling React Native

  1. Uses JavaScript styling
  2. Similar api, but not exactly, as css
  3. Uses Flexbox for layout
  4. Rely heavily on the documentation, especially at first

Styling React Native

// css
.header {
  width: 100%;
  background-color: red
}

// html
<div class="header" />

Web

// styles variable
styles = {
  header: {
    width '100%',
    backgroundColor: 'red'
  }
}

// style
<div style={styles.header} />

React

Styling React Native

// styles variable
styles = StyleSheet.create({
  header: {
    width '100%',
    backgroundColor: 'red'
  }
})

// style
<View style={styles.header} />

React Native

Styling React Native

Reusing styles in React Native vs Web

In web development, we reuse classes:

// css
.button {
  background-color: blue;
}

// html
<div>
  <button class='button'>Button1</button>
  <button class='button'>Button1</button>
  <button class='button'>Button1</button>
</div>

Styling React Native

Reusing styles in React Native vs Web

In React / React Native, we reuse components:

import React from 'react'
import { View, TouchableHighlight, Text } from 'react-native'

const Button = () => (
  <TouchableHighlight style={styles.button}>
    <Text style={styles.buttonText}>Hello World</Text>
  </TouchableHighlight>
)

class Home extends React.Component {
  render () {
    return (
      <View>
        <Button />
        <Button />
        <Button />
      </View>
    )
  }
}

APIs and Built In Components

Coming to React Native from the web

Built In  APIs and Components

Coming to React Native from the web

// Images (component)
import { Image } from 'react-native'

<Image
  source={require('./img/favicon.png')}
/>

<Image
  source={{ uri: 'http://www.myimage.com' }}
/>

// Alert (API)
import { Alert } from 'react-native'

Alert.alert('Alert Title', 'Alert Msg')

Browser Polyfills

Coming to React Native from the web

console.{log, warn, error, info, trace, table}

CommonJS require

XMLHttpRequest, fetch

{set, clear} {Timeout, Interval, Immediate}, {request, cancel}

AnimationFrame

navigator.geolocation

Get a quick start by using UI Libraries, like bootstrap for the web.

React Native Elements

Get a quick start by using UI Libraries, like bootstrap for the web.

React Native Material Design

Get a quick start by using UI Libraries, like bootstrap for the web.

Shoutem UI

Tips when beginning

React Native

  1. 99% of work can be accomplished from command line and any text editor
  2. Rely on third party modules for basic styling and functionality if not 100% certain on implementation
  3. Reach out to community for questions, a lot of helpful people out there
  4. Possibly get started with Expo

Getting Started with React Native

Have node installed, then:

npm install -g react-native-cli
react-native init ProjectName 
cd ProjectName
react-native run-ios
react-native run-android

Expo - Previously Exponent

Writing an Expo app is like writing a React Native app, except you never need to open Xcode / Android Studio

Entire environment is installed for you, with exception of Simulators

Expo

Expo - Previously Exponent

Getting Started

  1. Download Expo on Mac or Windows
  2. Create new project
  3. Make sure to have iOS or Android simulator installed.
  4. Run simulator (through exponent)
  5. Send link to anyone via email or text through expo, bypassing TestFlight

Creating New Project with Expo

Working with New Project in Expo

Working with New Project in Expo

Working with New Project in Expo

create-react-native-app

Expo - Sketch

React Native - Resources

Thanks for having me!

github - twitter - medium

KnowJS - React Native - Native App Development for Web Developers

By Nader Dabit

KnowJS - React Native - Native App Development for Web Developers

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