Video

The error message “Serve images in next-gen formats” is often flagged by tools like Google PageSpeed Insights or Lighthouse. It indicates that your website could benefit from using modern image formats In this video, I show how to fix this error This is part of my Udemy course "Boost Your Website Performance - The Practical Guide"Enroll here: www.udemy.com/course/boost-your-website-performance-...

Cumulative Layout Shift (CLS) measures the visual stability of a web page during loading. It quantifies unexpected layout shifts caused by moving elements. You can fix it using the CSS aspect ratio More about it in this video This is part of my Udemy course "Boost Your Website Performance - The Practical Guide"Enroll here: www.udemy.com/course/boost-your-website-performance-the-practical-guide/...

Suppose you have a large CSS or JS file referenced in your HTML page, but its content is not being used. Will the browser load it? Yes, it will, and this will be a total waste of time because it will delay loading the page for no reason. How can you identify these kinds of files? Use the Coverage tab in Chrome DevTools This is part of my Udemy course "Boost Your Website Performance - The Practi...

Should you lazy load all the images on the page? This video answers this question This is part of my Udemy course "Boost Your Website Performance - The Practical Guide"Enroll here: www.udemy.com/course/boost-your-website-performance-the-practical-guide/?referralCode=F28E3134284E023061DF

What is TBT - Total blocking time? How does it affect your web page performance? How can I find which function causes long TBT? All of these questions will be answered in this video This is part of my Udemy course "Boost Your Website Performance - The Practical Guide" Enroll here: www.udemy.com/course/boost-your-website-performance-the-practical-guide/?referralCode=F28E3134284E023061DF

Render-blocking resources, like JavaScript and CSS files, delay web page display and impact performance by delaying other resources. See this in action using WebPageTest in this video. This is part of my Udemy course "Boost Your Website Performance - The Practical Guide" Enroll here: www.udemy.com/course/boost-your-website-performance-the-practical-guide/?referralCode=F28E3134284E023061DF

The difference in performance between using a hero image instead of a hero div with a background image can be significant. Check the video to see why This is part of my Udemy course "Boost Your Website Performance - The Practical Guide" Enroll here: www.udemy.com/course/boost-your-website-performance-the-practical-guide/?referralCode=F28E3134284E023061DF

Using remote fonts can cause performance issues. In this video, I present this issue and suggest a solution This is part of my Udemy course "Boost Your Website Performance - The Practical Guide" Enroll here: www.udemy.com/course/boost-your-website-performance-the-practical-guide/?referralCode=F28E3134284E023061DF

Do you know the order in which the browser loads your HTML page resources? How long does it take for your hero image to appear in the viewport? How can you visualize the browser rendering pipeline using WebPageTest? This video has the answers This is part of my Udemy course "Boost Your Website Performance - The Practical Guide" Enroll here: www.udemy.com/course/boost-your-website-performance-th...

You should check the performance of your website by simulating users with a slow network. But how to do it using Chrome? In this video, I will show you how This is part of my Udemy course "Boost Your Website Performance - The Practical Guide" Enroll here: www.udemy.com/course/boost-your-website-performance-the-practical-guide/?referralCode=F28E3134284E023061DF

A lesson in my online course "Real-World TypeScript Unit Testing" Enroll via this link www.udemy.com/course/real-world-typescript-unit-testing/?referralCode=6B35B93853BC00B58172 course repository github.com/NathanKr/unit-testing-of-a-real-world-ts-system

A lesson in my online course "Real-World TypeScript Unit Testing" Enroll via this link www.udemy.com/course/real-world-typescript-unit-testing/?referralCode=6B35B93853BC00B58172 course repository github.com/NathanKr/unit-testing-of-a-real-world-ts-system

A lesson in my online course "Real-World TypeScript Unit Testing" Enroll via this link www.udemy.com/course/real-world-typescript-unit-testing/?referralCode=6B35B93853BC00B58172 course repository github.com/NathanKr/unit-testing-of-a-real-world-ts-system

Tools to test react applications - mostly react testing library. A lesson in my online course "Real-World TypeScript Unit Testing" Enroll via this link www.udemy.com/course/real-world-typescript-unit-testing/?referralCode=6B35B93853BC00B58172 course repository github.com/NathanKr/unit-testing-of-a-real-world-ts-system

The problematic of type any in typescript

The problems with string as action type in typescript

Unit test of async functions

userEvent , getByText and status role in testing library dom

Use getByRole in testing library dom

Motivation for testing library

spyOn and jsdom in frontend unit test

Jsdom setup and simple front-end unit test

Dom based unit testing tools

Use fake timers in unit test

Using mock and fn functions in unit test

Unit testing and refactoring a typescript module to a class

Front-end unit testing with spyOn

Front-end unit testing using jsdom

Motivation for mocks in unit testing