JSS VS ava

Most websites those days are SPA applications that render on the front-side. There is also this trend of CSS in JavaScript also knowns as JSS that is debatable (makes everything overcomplicated), but in some specific cases, can be justified and very useful.

> why tf aren't we using JS for styling already

People are and have been for quite a while

https://cssinjs.org/

JSS

It is possible. At its most simple, you could just modify the style property on every element. That's not generally considered best practice, but there are a number of "CSS-in-JS" libraries which streamline the process. The typically generate dynamic CSS classes and apply them to your elements. A big one is JSS.

import React, { useState, useEffect } from "react"; import Amplify, { API, graphqlOperation } from "aws-amplify"; import { createBlog } from "./graphql/mutations"; import { listBlogs } from "./graphql/queries"; import awsExports from "./aws-exports"; import { ListBlogsQuery } from "./API"; Amplify.configure(awsExports); const initialState = { name: "", body: "" }; const App = () => { const [formState, setFormState] = useState(initialState); const [blogs, setBlogs] = useState(); useEffect(() => { fetchBlogs() }, []); const handleInputChange = (event: React.ChangeEvent) => { setFormState({ ...formState, [event.target.name]: event.target.value }); }; const fetchBlogs = async () => { try { const blogData = (await API.graphql(graphqlOperation(listBlogs))) as { data: ListBlogsQuery } setBlogs(blogData.data); } catch (err) { console.log("Error fetching blogs" + err); } }; const addBlog = async () => { try { if (!formState.name || !formState.body) return; const blog = { ...formState }; if (blogs) { await API.graphql(graphqlOperation(createBlog, { input: blog })); await fetchBlogs(); setFormState(initialState); } } catch (err) { console.log("error creating blog: ", err); } }; return (

Amplify Todos

Create Blog {blogs && blogs?.listBlogs?.items?.map((blog, index) => { return (

{blog?.name}

{blog?.body}

); })}

); }; const styles = { container: { width: 400, margin: "0 auto", display: "flex", //real weird issue: https://github.com/cssinjs/jss/issues/1344 flexDirection: "column" as "column", justifyContent: "center", padding: 20, }, todo: { marginBottom: 15 }, input: { border: "none", backgroundColor: "#ddd", marginBottom: 10, padding: 8, fontSize: 18, }, todoName: { fontSize: 20, fontWeight: "bold" }, todoDescription: { marginBottom: 0 }, button: { backgroundColor: "black", color: "white", outline: "none", fontSize: 18, padding: "12px 0px", }, }; export default App;

Material UI v5 brought some amazing updates, but switching from JSS to Emotion had an arguably nasty side-effect: it was no longer as straightforward to group your component styles in classes. Fortunately, a fantastic library emerged that allowed developers to not only reduce the extreme pain from migrating all their classes from v4's makeStyles to emotion, but to also to continue to writing classes in practically the same syntax, with wonderful TS type-safety. This library was tss-react, and it was one of my favorite open source discoveries of 2021.

I started writing a long response, but I want to add that a simple CRA + JSS + TS (named exports only) stack solves or abstracts away most of these issues.

JSS

We use Jest Framework for testing. Jest is not a dogma, and, of course, in its place can be any other test runner, such as Mocha or Ava. Let's focus on tests. I'll provide a short example because I don’t want to waste your time. You can find the full version here. It's crucial to read the comments in the code below. Let's go!

> In the popular jest test runner, each test file is executed in its own child process.

Is that confirmed?

I've been following this issue:

https://github.com/jestjs/jest/issues/6957

And what Jest actually does is still kind of muddy.

In contrast to that, other test runners like AVA have a clear description what happens when:

https://github.com/avajs/ava/blob/main/docs/01-writing-tests...

I've been looking at using japa or ava for web server testing but was curious what others were using and why.

Continued work on the test suite. Implementing AVA, with snapshotting. Making a lot of effort to have the snapshot directory structure match the test262 test directory structure by generating AVA test files.

You might want to give ava a spin:

https://github.com/avajs/ava/

It has a TAP reporter, but more importantly, as opposed to the more popular solutions, like Jest, the way it achieves parallelism is explained in the docs and won't change anytime soon, thus preventing wonky, hard to debug errors which occur when this part is abstracted away.

I switched to ava for that reason and have been very happy with it. But vitest looks nice, too. Thanks for the pointer.

Runs unit tests using AVA.

Last but not least important are ava, uvu and tape; they are a really light and fast test runners.

I've had some good experiences with Ava + Sinon. I've personally disliked Jest because it seemed to do some weird trickery in the background that prevented me from using ES modules.

Ava for a simpler environment than Jest, which I usually use. I need to check how to mock ESM with it, though.