## Intro to React and Virtual DOM (https://medium.com/keepitlazy/intro-to-react-and-virtual-dom-f2bd1eda2feb)

boilerplate.js

<!-- Skipping all HTML5 boilerplate -->
<script src="https://unpkg.com/react@16.2.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.2.0/umd/react-dom.development.js"></script>

<!-- For JSX support (with babel) -->
<script src="https://unpkg.com/babel-standalone@6.24.2/babel.min.js" charset="utf-8"></script> 

<div id="app"></div> <!-- React mounting point-->

<script type="text/babel">
  class Watch extends React.Component {
    render() {
      return <div>{this.props.hours}:{this.props.minutes}</div>;
    }
  }

  ReactDOM.render(<Watch hours="9" minutes="15"/>, document.getElementById('app'));
</script>

create-element-example.js

// React.createElement naive implementation (using ES6 features)
function createElement(type, props, ...children) {
  return { type, props, children };
}

functional-component.js

const Watch = (props) =>
  <div>{props.hours}:{props.minutes}</div>;

ReactDOM.render(<Watch hours="Hello" minutes="World"/>, document.getElementById('app'));

js-vs-jsx.js

// Using JS with React.createElement
React.createElement('form', null, 
  React.createElement('div', {'className': 'form-group'},
    React.createElement('label', {'htmlFor': 'email'}, 'Email address'),
    React.createElement('input', {'type': 'email', 'id': 'email', 'className': 'form-control'}),
  ),
  React.createElement('button', {'type': 'submit', 'className': 'btn btn-primary'}, 'Submit')
)

// Using JSX
<form>
  <div className="form-group">
    <label htmlFor="email">Email address</label>
    <input type="email" id="email" className="form-control"/>
  </div>
  <button type="submit" className="btn btn-primary">Submit</button>
</form>

react-create-element.js

// Equivalent to JSX: <Watch hours="9" minutes="15"/>
React.createElement(Watch, {'hours': '9', 'minutes': '15'});

virtual-dom-json.json

{
   "type":"div",
   "props":{ "className":"form-group" },
   "children":[
     {
       "type":"label",
       "props":{ "htmlFor":"email" },
       "children":[ "Email address"]
     },
     {
       "type":"input",
       "props":{ "type":"email", "id":"email", "className":"form-control"},
       "children":[]
     }
  ]
}