All Jest related dependencies come installed as a part of the React project created using the npx command npx create-react-app <your app name>.

Jest is a JS test runner that has access to the DOM via jsdom. React Testing Library is a set of helpers that tests React components.


Did you know that Jest is developed by Facebook?

I wasn’t aware what kind of amazing technologies like React and Jest Facebook actually developed.

Jest is a JavaScript testing framework. It allows you to write tests in a very simple and quick way.

Look at my repo:

Getting started

If you…

A .env file is a simple configuration text file that is used to define some variables you want to pass into your application’s environment.

* .env.local: Local overrides. This file is loaded for all environments except test.

To read these values, there are a couple of options, but the easiest…

Why use Promises in your code?

To handle asynchronous operations in JavaScript.

You want your code to be still working and running while carrying out api calls for example.

A promise represents a single asynchronous operation that hasn’t been completed yet, but is expected in the future. …

What is Redux?

Redux is a Predictable State Container for JS Apps. It is mostly used as a state management tool with React. The state of your app is kept in a store and each component can access any state that is needed.

Why use it?

If you still don’t know if you need redux, you…

What is Next.js?

Next.js is an open-source React framework created by Vercel that enables functionality such as server-side rendering and generating static websites for React based web applications.

How to get started with Next.js?

Just enter

npx create-next-app

in the terminal and the automatic settings will be installed.

If you are going to use typescript, write:

npx create-next-app –typescript

The z-index property define the stack order of an element.

An element with greater stack order is always in front of an element with a lower stack order.

Not setting a position: fixed, relative, absolute or sticky for an element.

z-index requires an element’s positioning to be either fixed, relative, sticky or absolute.

Positioning Recap:

HTML elements are positioned static by…

What is the Shadow DOM?

The Shadow DOM is a “DOM within a DOM”. It is an isolated DOM tree with its own elements and styles, completed isolated from the main DOM.

With Shadow DOM you can specify CSS style to a specific DOM subtree and isolate that subtree from…

Damaris Göbel

I like to do crazy things with CSS & JavaScript. My brain occasionally runs out of memory so I need to write down my thoughts.

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