I wanted to show or hide a little panel based on the mouse hover status.

When I hovered a link, the panel would show up.

Then I could enter this panel with the mouse, and when I moved the mouse away, the panel would hide.

Like the Twitter profile that shows when you move the mouse upon the name of a person:

on the <a> element that triggered the panel to show up, I added the event onMouseEnter:

<a
  onMouseEnter={() => {
    setShowCard(true)
  }}
>flavio</a>

so the panel would show when I hovered it with the mouse, because it was shown depending on the showCard state variable I had set before:

const [showCard, setShowCard] = useState(false)

Then I had the ProfileCard component but I couldn’t just do:

<ProfileCard
onMouseEnter={() => {
  setShowCard(true)
}}
onMouseLeave={() => {
  setShowCard(false)
}}
/>

because it didn’t work. ProfileCard is not a DOM element, so it didn’t get the events fired to respond to.

What I had to do was to pass onMouseEnter and onMouseLeave as props to the ProfileCard component, then identify the correct DOM element inside it that could receive those events, and attach the event handler there. In this case, I used the container div:

const ProfileCard = ({
  onMouseEnter,
  onMouseLeave
}) => (
  <div
    onMouseEnter={onMouseEnter}
    onMouseLeave={onMouseLeave}>
      ...

Now leaving the panel would hide it.

Lessons in this unit:

0:	Introduction
1:	Setting up a React project with Vite
2:	React Components
3:	Introduction to JSX
4:	Using JSX to compose UI
5:	The difference between JSX and HTML
6:	Embedding JavaScript in JSX
7:	Handling user events
8:	Install the React Developer Tools
9:	Getting started with JSX
10:	How to return multiple elements in JSX
11:	How to learn React
12:	Should you use jQuery or React?
13:	React concepts: declarative
14:	The Virtual DOM
15:	The roadmap to learn React
16:	What’s new in React 19
17:	How to install React
18:	The React Fragment
19:	React, how to transfer props to child components
20:	React PropTypes
21:	▶︎ React DOM events on components
22:	How to pass a parameter to event handlers in React