CSS-in-JS provides a syntax for turning your JavaScript into styles the browser can apply. Regardless of the framework you use, the result will look something like Listing 1. Listing 1.

The world wide web basically runs on JavaScript, HTML, and CSS. Unfortunately, JavaScript lacks several features that would help developers use it for large-scale applications. Enter TypeScript .

CSS: Enter CSS to be applied to the HTML used in your tests. It is placed between <style> elements in the header portion of the page. HTML: This area allows you to enter HTML to be used in your tests.