mirror of
https://github.com/kay-is/react-from-zero.git
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57 lines
1.8 KiB
HTML
57 lines
1.8 KiB
HTML
<!doctype html>
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<title>14 References - React From Zero</title>
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<script src="https://unpkg.com/react@16.4.0/umd/react.development.js"></script>
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<script src="https://unpkg.com/react-dom@16.4.0/umd/react-dom.development.js"></script>
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<script src="https://unpkg.com/create-react-class@15.6.3/create-react-class.js"></script>
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<script src="https://unpkg.com/@babel/standalone/babel.min.js"></script>
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<div id="app"></div>
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<script type="text/babel">
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// Sometimes we need some state from an element or a component
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// or it has to be directly modified somehow. For
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// this case, we can tell React to create references.
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var RefComponent = createReactClass({
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// First we tell React to render an input with a ref callback, it
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// will be called, when the DOM of the input element is available
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render: function() {
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return (
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<div>
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<input ref={this.handleRef} />
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<button onClick={this.handleClick}>Do Something</button>
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</div>
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);
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},
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// This callback is called when the input element was mounted into
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// the DOM and again, with null, when it was unmounted again
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// For elements the rendered DOM node will be stored
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// For components the instance of the component will be stored.
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handleRef(nameInput) {
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// We save a reference to it for later use.
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this.nameInput = nameInput;
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},
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// This callback is called when the button is clicked
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// and uses this.nameInput to read out the value of the input.
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handleClick: function() {
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console.log(this.nameInput.value);
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}
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});
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// Since references are local to their component
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// they can be used as local IDs to get elements
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// and don't override each other when another
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// instance of the component is created
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var reactElement = (
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<div>
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<RefComponent />
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<RefComponent />
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<RefComponent />
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</div>
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);
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ReactDOM.render(reactElement, document.getElementById("app"));
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</script> |