Software

Fix Seeing “0” in Your JSX Code


The early days of the web felt like the wild west when it came to coding practices — just make it work. Then we became enlightened to better practices, separating HTML from CSS and JavaScript. Then came React and JSX, where we combine JavaScript, HTML, and even CSS with Styled Components — what an elegant mess we’ve made!

Every once in a while part of that mess is me seeing 0 displaying in the output of my JSX code, and I’m reminded why: improper handling of variable typing, combined with using &&. Let me explain!

One of the popular patterns in JSX is:

<div>Some header</div>
{someValue && <div>Some header</div>}

The pattern makes sense but check out the difference in outputs between string and number types:

"0" && "Thing"
> "Thing"
0 && "Thing"
> 0

Note that a string value of 0 allows the second value to be returned, but a number typed 0 simply returns the 0. The best practice is always to cast the value to a Boolean in your JSX:

{Boolean(value) && ....}

Typescript and even PropTypes can help to catch these issues but even seasoned veterans sometimes hit these pain points.

  • MooTools Fun with Fx.Shake

    Adding movement to your website is a great way to attract attention to specific elements that you want users to notice. Of course you could use Flash or an animated GIF to achieve the movement effect but graphics can be difficult to maintain. Enter…

  • Fullscreen API

    As we move toward more true web applications, our JavaScript APIs are doing their best to keep up.  One very simple but useful new JavaScript API is the Fullscreen API.  The Fullscreen API provides a programmatic way to request fullscreen display from the user, and exit…



Source link
Show More

admin

Makes Noise is a blog where you can find all the juicy details on a variety of topics including health and fitness, technology, lifestyle, entertainment, love and relationships, beauty and makeup, sports and so much more. The blog is updated regularly to make sure you have all the latest and greatest information on the topics that matter most to you.

Related Articles

Leave a Reply

Your email address will not be published.

Back to top button