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ReactJS

Boilerplates
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🌈 React Cheat Sheet

A simple cheat sheet for facilitate the process in the workshops and event about React. Let me know if you see any problem, I'll love a pull request for improve this document.


Installation

  • Add the tags in your HTML
    <script src="https://unpkg.com/react@16/umd/react.development.js" crossorigin></script>
    <script src="https://unpkg.com/react-dom@16/umd/react-dom.development.js" crossorigin></script>
  • Run this scripts in your terminal
    $ npm install react react-dom

No configuration

Just start with React no configuration (run the scripts bellow in your terminal)

  • Install the React
    $ npm install -g create-react-app
  • Create your application (change myApp to your application name)
    $ create-react-app myApp
  • Go to the application folder and install the dependencies
    $ cd myApp
    $ npm install
  • Start your application
    $ npm start
  • Go to the browser by URL bellow and see your beautiful application

ReactDOM

import React, { Component } from 'react';
import ReactDOM from 'react-dom';

ReactDOM.render( <h1>Hello React Ladies</h1>, document.getElementById('root') );

Functional Stateless Component

import React from 'react';

const Button = () =>
<button> Apply</button>

export default Button;
import React from 'react';

const Button = ({ onClick, className = 'button', children }) =>
<button
onClick={ onClick }
className={ className }
type='button'
>
{ children }
</button>

export default Button;

Class Component

import React, { Component } from 'react';

class MyComponent extends Component {
render() {
return (
<div className="main">
<h1>Helo Devas</h1>
</div>
);
}
}

export default MyComponent;
import React, { Component } from 'react';

class MyComponent () extends Compnent {
constructor ( props ) {
super(props);
this.state = { message: 'Helo Devas' }
};

render() {
return (
<div className="main">
<h1>{ this.state.message }</h1>
</div>
);
}
}

export default MyComponent;


Composition

import React, { Component } from 'react';
import ReactDOM from 'react-dom';

class Love extends Component {
render() {
return (
<div clssName="love">
<h1>My love</h1>
</div>
);
}
}

class LoveList extends Component {
render() {
return (
<div>
<Love />
<Love />
<Love />
<Love />
</>
);
}
}

ReactDOM.render(
<Love />,
document.getElementById(´root´)
);


Module component

//App.js
import React, { Component } from 'react';

class App extends Component {
render() {
return (
<div className="app">
<p>My App</p>
</div>
);
}
}

export default App
//Index.js
import React, { Component } from 'react';
import ReactDOM from 'react-dom';
import App from './App.js';

class Index extends Component {
render() {
return (
<div className="app">
<App />
</div>
);
}
}


ReactDOM.render (
<Index />,
document.getElementById('root')
);


Hot Module Replacement

  • Retain application state which is lost during a full reload.
  • Save valuable development time by only updating what's changed.
  • Tweak styling faster -- almost comparable to changing styles in the browser's debugger.
import React, { Component } from 'react';
import ReactDOM from 'react-dom';
import MyComponent from './MyComponent';

ReactDOM.render( <MyComponent />, document.getElementById('root') );

if (module.hot) {
module.hot.accept();
}

Props

import React, { Component } from 'react';

class App extends Component {
render() {
return (
<div className="app">
<p>My App {this.props.name}</p>
</div>
);
}
}

class Index extends Component {
render() {
return (
<div className="app">
<App name="Simone"/>
</div>
);
}
}

export default Index;

State

import React, { Component } from 'react';

class App extends Component {
constructor(props) {
super(props);
this.state = {messages: 0};
}

render() {
return (
<div className="app">
<p>My messages: {this.state.messages}</p>
</div>
);
}
}

export default App;

Methods and Events

import React, { Component } from 'react';

class App extends Component {

escreve() {
console.log("Eu te amo");
}

render() {
return (
<div className="app">
<button onClick={this.escreve}>save</button>
</div>
);
}
}

export default App;

State manipulation

import React, { Component } from 'react';

class App extends Component {
constructor() {
super();
this.state = { like: 0 };
}

isLiked = () => {
this.setState({ like: this.state.like + 1});
}

render() {
return (
<div className="app">
<button onClick={ this.isLiked }>{ this.state.like }</button>
</div>
);
}
}

export default App;
import React, { Component } from 'react';

class App extends Component {
constructor() {
super();
this.state = { messages: ['JS', 'React'] };
}

addMessages = () => {
const updateMessages = [...this.state.messages, 'Polymer']
this.setState({ messages: [...updateMessages] })
}

render() {
return (
<div className="app">
<button onClick={this.addMessages}>add</button>
{console.log(this.state.messages) /* ['JS', 'React', 'Polymer'] */}
</div>
);
}
}

export default App;

d

Bindings

import React, { Component } from 'react';

class MyComponent extends Component {
constructor () {
super();

this.state = { list: list };

this.doSomethingElse = this.doSomethingElse.bind(this);
};

doSomething = () => {
// do something
/* if don't have a parameter, you can use arrow function
and don't need to use bind */
}

doSomethingElse ( itemId ) {
// do something else
}

render() {
return (
<div className="main">
{this.state.list.map( item =>
...
<button
onClick={ this.doSomething }
type="button"
>
Some Thing
</button>

<button
onClick={ () => this.doSomethingElse( item.objectID ) }
type="button"
>
Some Thing Else
</button>
...
)}
</div>
);
}
}

export default MyComponent;

ES6

Arrow Functions

Syntax

Basic syntax

( param1, param2, ..., paramN ) => { statements }

( param1, param2, ..., paramN ) => expression

( singleParam ) => { statements }

singleParam => { statements }

() => { statements }

Advanced Syntax

params => ({ foo: bar }) /* return an object literal expression */

( param1, param2, ...ladies ) => { statements } /* rest parameters */

( language = JS, ladies, ..., framework = React ) => { statements } /* default parameters */

const sum = ( [num1, num2] = [1, 2], { x: num3 } = { x : num1 + num2 } ) => num1 + num2 + num3 /* destructuring within the parameter list */
sum() /* 6 */

Spread Operations

Spread in array literals

const basics = [ 'JS', 'HTML', 'CSS' ];
const frameworks = [ 'React', 'Vue' ];
const web = [ ...basics, ...frameworks ];
console.log(web); /* ['JS', 'HTML', 'CSS', 'React', 'Vue'] */

const addWeb = [ ...web, 'al11' ];
console.log(addWeb); /* ['JS', 'HTML', 'CSS', 'React', 'Vue', 'al11'] */

Spread in object literals

const basics = { behavior: 'JS', markup: 'HTML' };
const style = 'CSS';
const web = { ...basics, style };
console.log(web); /* { behavior: "JS", markup: "HTML", style: "CSS" } */

const devFront = { framework: 'react', event: 'React Conf' };
const devBack = { framework: 'django', state: 'cool' };

const cloneDev = { ...devFront };
console.log(cloneDev); /* { framework: 'react', event: 'React Conf' } */

const merged = { ...devFront, ...devBack };
console.log(cloneDev); /* { framework: 'django', event: 'React Conf', state: 'cool' } */