React JS

Tutorial 

React

A Javascript UI Framework

HTML

Javascript

CSS

DOM

Structure

Style

interactive

effect

+

+

Traditional Web View

With MVC 

React

Everything is Component

Start React

<html>
  <head>
    <title>Sample App</title>
  </head>
  <body>
    <div id="root"><!-- CONTENT --></div>
  </body>
  <script src="bundle.js"></script>
</html>

HTML ENTRY

public/index.html

Render

Target

JSBundle by Webpack

var React = require('react');
var ReactDOM = require('react-dom');
var Demo = require('./demo');

function render () {
    ReactDOM.render(
        ( <Demo /> ), 
        document.getElementById('root'));
}

render();

Application

src/app.jsx

VDOM -> DOM

React component (JSX)

var React = require('react');

const Demo = React.createClass({
    getInitialState () {
        return{
            data: 'Hello world';
        }
    },
    handleClick(e){
        console.log("I've been click");
    },
    render(){
        return(
            <div onClick={this.handleClick}>
                {this.state.data}
            </div>
        );
    }
});

export default Demo;

React component

src/demo.jsx

set state

VDOM

ReactElement

  • type
  • props
  • key
  • ref
<Input type="text" key={object.id} ref="nameInput" anyprops={this.state.data} >

TRY IT

Generate A list has 10 inputs

10 min

Thinking : 如果是10個有些微不同的input呢？

Props & State

State

  • Every Component own itself state
  • State init before component mount
  • If data would be changed, it must be state

this.setState({ state : newState })

Whenever you call, component reRender

getInitialState () {
        return {
            data: 'initial data'
        }
    },

Props

  • Inherit from parent component
  • Should not be changed ( one way data-flow)
  • Can be function or object
//parent
<Test data="123"/>

//child
this.props.data  => "123"

Props or State?

constructor(props){
    super(props);
    this.state = {data: props.data}
}
render(){
    return(<div>{this.state.data}</div>)
}

或者

render(){
    return(<div>{this.props.data}</div>)
}

TRY IT ?

Props or State?

constructor(props){
    super(props);
    this.state = {data: props.data}
}
render(){
    return(<div>{this.state.data}</div>)
}

或者

render(){
    return(<div>{this.props.data}</div>)
}

When parent props change, the first way nothing happened. WHY?

React LifeCycle

  • Mounting: A component is being inserted into the DOM.
    • ​getInitialState
    • componentWillMount
    • componentDidMount
  • Updating: A component is being re-rendered to determine if the DOM should be updated.
    • ​componentWillReceiveProps(object nextProps)
    • shouldComponentUpdate(object nextProps, object nextState): boolean
    • componentWillUpdate(object nextProps, object nextState)
    • componentDidUpdate(object prevProps, object prevState)
  • Unmounting: A component is being removed from the DOM.
    • componentWillUnmount()

LifeCycle 

VERY important

Practice :

Log it whenever you use lifecycle method

React Tips

Callback props

//parent
callback(returnData){
    this.state.data = returnData;
    this.setState({ data:this.state.data});
},
render(){
    return(
        <Test returnValue={this.callback} />
    );
}

//child
let data = '123';
this.props.returnValue(data);

When parent want child's data

TRY IT

Generate A list has 10 inputs with different type & default value

10 min

Hint : component reuse

React JS

By Derek silenceshia

Made with Slides.com

React JS

a basic react toturial

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