ReactJS 

@basarat

Code

JavaScript Recap

var foo = {
    bar: 123
};

JavaScript Recap

var {bar} = foo;

// Essentially
var {bar} = {
    bar: 123
};
// Essentially
var bar = foo.bar;

JavaScript Recap

var foo = function () { return 123 };

var foo = () => 123;

JSX premier

TypeScript TSX

JSX

let rendered = <div/>

console.log(rendered);

JSX

let rendered = <div>Hello World</div>;

console.log(rendered);

JavaScript Recap

// whole line == "Statement"
var foo = 123; 

// A sourcefile is just
// a bunch of *statements* ;)

var foo =  
    /* this is an expression */ 123;

JavaScript Recap

// Warning: Invalid JavaScript! 

var foo = { 
  bar : if (true) { console.log(123) }
}

JavaScript Recap

// \o/

var foo = { 
  bar : true && 123
}

Escaping

let message = "Hello World";

let rendered = <div>{message}</div>;

Logic

let condition = true;

let rendered = <div>
  {
    condition 
    && <div>
        Will only show if condition is true
    </div>
  }
</div>;

JS Keywords

<div className="foo"/>

<label htmlFor="foo"/>

These match the JavaScript access for these in browser DOM e.g.`node.className` 

var foo = document.createElement('div');
foo.

Comments

var content = (
  <Nav>
    {/* We need more Person */}
    <Person
      // Name only set if logged in
      name={window.isLoggedIn ? window.name : ''}
    />
  </Nav>
);

Render convention: ();

return (
  <Nav>
    {/* We need more Person */}
    <Person
      // Name only set if logged in
      name={window.isLoggedIn ? window.name : ''}
    />
  </Nav>
);

What is

A data model

=====>

DOM

Display!

const rendered = <div>Hello World</div>

// Render to DOM
ReactDOM.render(
  rendered,
  document.getElementById("root")
);

// Render on server
const str = ReactDOMServer.renderToString(rendered);

Everything is a component

https://upload.wikimedia.org/wikipedia/commons/4/47/River_terrapin.jpg

What is a component?

Props

=>

Component Instances

Simples

const Body = () => rendered;

Simples

const Body = ({body})=> <div>{body}</div>

Composition

const Headline = ({title}) =>
  <div style={{ fontSize: "24px" }}>{title}</div>;

const News = ({title, body}) =>
  <div>
    <Headline title={title}/>
    <Body body={body}/>
  </div>;

Types!

const News = 
    ({title, body}: {title: string, body: string}) =>

Stateful components

Props =>

(state) => 

Component Instances

interface Props {
  body: string;
}

export const Body = (props: Props) =>
  <div>{props.body}</div>
interface Props {
  body: string;
}

interface State {
}

export class Body extends React.Component<Props, State>{
  render() {
    return <div>{this.props.body}</div>;
  }
}

interface Props {
  body: string;
}

interface State {
  count: number;
}

export class Body extends React.Component<Props, State>{
  constructor(props: Props) {
    super(props);
    this.state = {
      count: 0
    }
  }
  render() {
    return <div>{this.props.body} - {this.state.count}</div>;
  }
}

interface Props {
  body: string;
}

interface State {
  count: number;
}

export class Body extends React.Component<Props, State>{
  constructor(props: Props) {
    super(props);
    this.state = {
      count: 0
    }
    setInterval(this.incrementCount, 1);
  }

  incrementCount = () => {
    this.setState({ count: this.state.count + 1 })
  }

  render() {
    return <div>{this.props.body} - {this.state.count}</div>;
  }
}

interface Props {
  body: string;
}

interface State {
  count: number;
}

export class Body extends React.Component<Props, State>{
  constructor(props: Props) {
    super(props);
    this.state = {
      count: 21341231312
    }
  }

  interval: number;
  componentDidMount() {
    this.interval =
      setInterval(() => this.setState({ count: this.state.count + 1 }));
  }
  componentWillUnmount() {
    clearInterval(this.interval);
  }

  render() {
    return <div>{this.props.body} - {this.state.count}</div>;
  }
}

Life Cycle

https://facebook.github.io/react/docs/component-specs.html#lifecycle-methods

componentDidMount #

componentWillReceiveProps #

shouldComponentUpdate #

componentWillUpdate #

componentDidUpdate #

componentWillMount #

constructor

XHRs

propsToState

this. state == state

componentWillUnmount #

dispose()

JavaScript Emit

Constructor Functions

return <Fancy ref="root"/>;
return React.createElement(Fancy,
    {"ref": "root"}
);

Constructor Functions

return <div ref="root"/>;
return React.createElement("div", 
    {"ref": "root"}
);

Dom

div

Component

Div

TIPS

Render

<noscript/>

Two Way DataBinding

Two Way DataBinding

Say no to cycles

Input

render() {
    return <input 
        type="text" 
        value={this.state.message} 
        onChange={(event)=>this.setState({message:event.target.value})} />;
}

Life

Code

Thank you

@basarat

ReactJS Presentation Melbourne FEnders

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ReactJS Presentation Melbourne FEnders

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