Images often are problematic while we creating web page . Displaying larger image on larger screen is a better for user experience, but displaying large photo on small screen, e.g. on a phone, may unnecessarily delay page loading. Therefore, a good solution is to “serve” images with different sizes and weight for different screens.

Sometimes we want that picture on page shrinks when browser window shrins. This can be easily achieved by using a short css entry.

Every junior front-end developer should know what hoisting is. This issue can be easily understood, so if you have not heard of it before, you can quickly catch up:

Tworząc strony internetowe zdarza się, że chcemy, aby div z określonymi informacjami zajmował całą wysokość okna, niezależnie od wysokości tego okna. Wiadomo, że ustawiając wysokość dziecka na 100% zajmuje ono całą przestrzeń swojego rodzica. Zatem aby div zajmował całą wysokość okna, wszyscy jego rodzice muszą także mieć ustawioną taką wysokość. When we create websites, we […]

The problem of centering divs or text is quite common and I often had to spend more time fixing it than I would like. Sometimes the situation is simple and using one of the basic methods, like margin: 0 auto solves the case, and sometimes you have to think a little more. Therefore, below are […]

Depending on what you currently want to achieve, you can use several solutions to check if the string contains substring:

We have array [“javascript”, “jest”, “fajny”, 1, 2, 3]. Let’s see what’s happends, if we want to copy it and assign it do variable, and next modify it:

By sorting an array of numbers and using the built-in sort() function, you’ll definitely notice that, by default, sorting doesn’t go from smallest to largest, but alphabetically.

React Native applications often use two or more navigators at once. At first, I had a problem with the combination of stack navigator and drawer navigator, fortunately I combined them in way, that they work properly and now I can share this knowledge.