mirror of
https://github.com/kay-is/react-from-zero.git
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94 lines
2.6 KiB
HTML
94 lines
2.6 KiB
HTML
<!doctype html>
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<title>9 Component Classes - React From Zero</title>
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<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.0.1/react.js"></script>
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<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.0.1/react-dom.js"></script>
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<script src="https://cdnjs.cloudflare.com/ajax/libs/babel-core/5.8.34/browser.min.js"></script>
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<div id='app'></div>
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<script type="text/babel">
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// Often a component needs to maintain some internal state
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// for example if there is interaction involved
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// in this case a component function is not sufficient
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// the component function can only has properties and no state
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// we need a component class with a render function
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var MyComponent = React.createClass({
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// used for type-checking of the properties
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// same as with the component function
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propTypes: {
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color: React.PropTypes.string,
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},
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// this method will be called by React
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// before the components gets mounted into the DOM
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getDefaultProps: function() {
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return {
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color: 'green'
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}
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},
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// this method will be called by React
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// before the components gets mounted into the DOM
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// if this method is missing, this.state will be undefined
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getInitialState: function() {
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// The state can be any JavaScript value, often it is an object
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return {
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times: 0
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}
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},
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// this method handles all the clicks on the <span> element
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handleClick: function() {
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// every call of this.setState() triggers a call of render() with
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// the new values in this.state
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this.setState({
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times: this.state.times + 1
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})
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},
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// this method will be called by React
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// after the component got mounted into the DOM
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// also every time this.setState() was called
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// it's like the component function from before
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// but without a props argument
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render: function() {
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// using the prop given by the creator of this component
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// properties are now in this.props instead of the props argument
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var style = {
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color: this.props.color
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}
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// returning an element with a click-handler and the props and
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// state values. state is stored in this.state
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return <span onClick={this.handleClick} style={style}>
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Clicked {this.state.times} times
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</span>
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},
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})
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// creating some instances of the interactive stateful component class
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// one with default color
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// Everything works exactly like with the simpler component functions
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// The interface has not changed for the user of this component
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var reactElement = <div>
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<MyComponent color='red'/>
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<br/>
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<MyComponent color='blue'/>
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<br/>
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<MyComponent/>
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</div>
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var renderTarget = document.getElementById('app')
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ReactDOM.render(reactElement, renderTarget)
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</script>
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