Docker Start Docker from scratch
Docker is widely used but I haven't used it in my career. However, it is one of very useful softwares so it's time to le...
Docker 
JavaScript/TypeScript Difference between for, while, forEach, for-in and for-of
A lot of languages support several ways for loop logic. Typescript supports following ways for example. whileforfor in f...
JavaScript/TypeScript async/await with Promise in TypeScript
Using promise makes the code much faster. This post explains the basic and advanced usage.
JavaScript/TypeScript How to write unit tests for a singleton class
Once a static field value changes in unit tests, the change applies to other tests because it's static. It's important to split it into two classes. One class has the main logic and the other stores the class to provide it as singleton.
Other techs Start Powershell with specified execution policy without changing default
How to start powershell I often starts powershell.exe from an explorer instead of command prompt because it looks better...
JavaScript/TypeScript Using spread operator for process.env
I faced strange behavior when I used spread operator for process.env. In my project, our main source is Typescript but w...
JavaScript/TypeScript How to write good unit tests?
Unit Test makes your software better in terms of not only quality but also class structure because you need to separate ...
Docker Dev Environment in Docker Container
When we try something new we need to install something and then remove it if it is no longer necessary but our PC will g...
JavaScript/TypeScript Dependency injection in Typescript. Constructor? Setter? Factory method?
Decoupling class relationships is important for unit testing. Less cohesion makes writing unit tests easier. This post shows 3 ways to do it. Constructor injection, setter injection, and using the factory method to inject the desired instance.