EDIT: Ok, after publishing I realized that "nothing else" is an exaggeration. There is quite a bit of CSS too. But no other JS dependency 🙈

Tooltips are a fantastic way of adding context to a piece of UI.

Recently I had to use lots of them at work. And I'm a rather lazy person, so to make it easier I created a <Tooltip /> component that I could use to add tooltips to pretty much anything.

It is a no-sweat component, with no dependency other than React itself.

Be aware that most of the patterns applied here are not exclusive to React so you may learn a few new things even React is not your cup of tea. 🙂

Here's a demo before we move into the details:

How to make it

What makes this component so good is that it leverages good old CSS sorcery with the flexibility of React children prop. We only need two files to make it work: Tooltip.css and Tooltip.js.

Let's talk about the CSS of it first.

Tooltip.css

There's a handful of techniques at play here:

1. Custom properties (CSS vars) that control color, spacing and arrow size
2. CSS border triangles and before pseudo-elements to make the arrows
3. Some smart absolute positioning and wrapping to put everything in the right place

Have a look at the Tooltip.css file.

You can see that half of it is styling to make the tooltip appear in different directions. A CSS preprocessor could make this code leaner but remember, we are keeping it simple.

The biggest takeaway of Tooltip.css is understanding that by wrapping a React component with <Tooltip> we are also wrapping it with an element styled by the Tooltip-Wrapper class.

That CSS class anchors the positioning of the tooltips with position: relative. That way we can use position: absolute in each tooltip with its top, right, bottom, and left values relative to the element we are wrapping.

Now that we understand that Tooltip.css handles how the tooltip looks and where it goes, let's talk about its .js counterpart.

Tooltip.js

Tooltip.js does four important things:

1. It takes everything inside a <Tooltip> component and moves it inside a div with Tooltip-Wrapper class by using props.children
2. It controls what content will be inside the tooltip bubble with props.content
3. It controls where the bubble will appear using the value passed to props.direction as a class.
4. It controls when it shows by listening to onMouseEnter and onMouseLeave events

Here, have a snoop at Tooltip.js:

Can you see how it works together with Tooltip.css?

The biggest takeaway of this file is that it has the minimal necessary logic to make CSS shine. All the work it does is moving the props you passed to <Tooltip> into the right places.

So at the end of the day (or at the end of the reconciliation 😄), all that Tooltip.js does is transforming this:

<Tooltip content="Hello, I'm a tooltip" direction="right">
  <button>I'm a button</button>
</Tooltip>

Into this:

<div
  className="Tooltip-Wrapper"
  onMouseEnter={showTip}
  onMouseLeave={hideTip}
>
  <button>I'm a button</button>
  {active && (
    <div className={`Tooltip-Tip right`}>
      Hello, I'm a tooltip
    </div>
  )}
</div>

How to use it

After learning how it works, the "how to use it" should be pretty simple to grasp.

All you need to do is import the Tooltip component and use it as a wrapper. Make it go above anything you want to show a tooltip on hover.

It takes three props:

1. content, which will be what's inside the tooltip
   • Required, It can be anything JSX, text, images, other components, it's up to you
2. direction, which controls where the tooltip will show
   • Optional, accepts top, right, bottom, and left. Defaults to top
3. delay, how much time, in milliseconds, it takes for the tooltip to show.
   • Optional, defaults to 400ms

Add a simple wrap with a some of these props and bam now every hover on anything that is inside <Tooltip> will show a small balloon of content.

Here's how I did it in the demo:

Pretty cool, right?

What I love the most about modern web development is how components make stuff easier to implement after some initial setup.

Doing the same thing during jQuery times would take a lot of repetition, duplication, and much more elbow grease.

And as a final reflection, I'm sure that some things in front-end look crazy complex now but these kinds of techniques make me feel that we are moving in the right direction.

And that's it, thanks for reading. I hope this article is useful on your front-end journey!

As always, comments and feedback are super welcome, so what would you change or improve in this implementation?

Cover photo by Drew Beamer on Unsplash

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