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Components and Advanced JSX
Use an Event Listener in a Component

Render functions often contain event listeners. Here’s an example of an event listener in a render function:

render() { return ( <div onHover={myFunc}> </div> ); }

Recall that an event handler is a function that gets called in response to an event. In the above example, the event handler is myFunc().

In React, you define event handlers as methods on a component class. Like this:

class MyClass extends React.Component { myFunc() { alert('Stop it. Stop hovering.'); } render() { return ( <div onHover={this.myFunc}> </div> ); } }

Notice that the component class has two methods: .myFunc() and .render(). .myFunc() is being used as an event handler. .myFunc() will be called any time that a user hovers over the rendered <div></div>.

Instructions

1.

In app.js, find the <button></button> inside of the render function.

Give this <button></button> an onClick attribute. The attribute’s value should be the .scream() method.

Feel free to use the example code as a guide.

2.

At the bottom of the file, render a <Button /> using ReactDOM.render(). For ReactDOM.render()‘s second argument, pass in document.getElementById('app').

Once your component renders, click on the button in the browser. Bone-chilling!

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