In the previous part — — we were looking for solutions of quite simple task — printing isosceles triangle to console. In second part let us focus on a bit more complex problem — printing rectangular triangle with parametric angle. …


There is really high chance that in some point in the past you have typed above phrase in Google or Stack Overflow search field. This problem is so common that it is the most voted question under javascript tag on . …


How to optimize Fibonacci sequence elements calculation in JavaScript

Fibonacci sequence in nature

TLDR: Implementing Fibonacci sequence is so common on programming interviews that it is worth to master this problem. Learn about simple optimization method of recursive implementation of this sequence.

Have you ever need to implement Fibonacci sequence calculating program as part of job interview? So many hands up! Let us…


TLDR: Even as simple problem as printing triangle in console can have different interesting solutions. It is worth to tackle problems in systematic way and go from easiest to optimal to beautiful solutions.

Do you think printing triangle to console is easy and boring task? I will try to change…


How I’ve got an interview invitation, how I prepared to the interview and how it went.

At the middle of February I was quite surprised when I’ve got a message on LinkedIn from Amazon recruiter. I was very excited and responded in a matter of minutes. Recruiter informed me that first step of recruitment process is technical screening. …


JavaScript provides Object methods which can restrict mutability of an object. The preventExtensions(), seal() and freeze() methods are great tools, although they do not exactly work as one might intuitively expect.

What is immutability and why is it desired?

A short answer to the first question is as follows:

An object is immutable when it cannot be changed (mutated).

But what exactly does “changed” mean? Does changing a newly created own property count? Yes, obviously. But does changing an inherited property in a prototype object count as “changed” in…

Maciej Twaróg

Programming computers is my hobby

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store