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How to Process Events

In this section, you will learn how to describe the component behavior when an event happens. For example, when mousing over or clicking on a component.

To add interception of an event to a component, add the event name and the function as a prop that will process it, for example:

const onEnterEvent = e => console.log('Cursor hovers over element ',;
const onLeaveEvent = e => console.log('Cursor doesn't hover over element ',;
return (
Component sensitive to cursor hover

In this example, we added two custom functions: onEnterEvent and onLeaveEvent — which display a message in the console and are called when the onMouseEnter and onMouseLeave events happen respectively. You'll learn how to change the component state, styles, etc. in the following sections.

Each event returns an object with data, which we called "e". There you can get the type of the event (e.type), the element it was applied to (, and other less frequently used data.

Almost any event can be interrupted by calling e.preventDefault() in its function. For example, to prohibit copying text, hover over an element or a form.