HTTP cookies are small bits of text that are included with each HTTP request made from a user’s web browser to web servers. HTTP is a stateless protocol which means each requests is treated as a unique command, and no state data is maintained. Cookies were designed to fill this gap, and allow servers to associate data with user’s as they traverse sites. Cookies are commonly used by sites to hold authentication tokens, tracking ids, or save user preferences.

If you were expecting a phone call from a friend, you (hopefully) wouldn’t sit by the phone and continuously pick it up to see if your friend was on the other end. Instead, you’d wait to be notified of an incoming call when the phone started ringing or vibrating. Sitting by the phone and picking it up over and over again is a form of what’s known as polling.

What’s so Magical About Magic Strings?

Magic strings are string literals strewn about a code base that apply some kind of limitation to the code. They can be used to filter valid input, constrain parameters, or control the behavior of code.

For beginners TypeScript is like the carrot on the end of the stick, always just out of reach no matter how hard you try. Everyone touts how it’s “JavaScript that scales”, and once you use it you’ll never go back. But finding a decent tutorial on how to set up a new TypeScript project is quite the challenge. Many tutorials are out-dated and want you to install other packages such as gulp, jump through hoops, or even sacrifice your first born child (okay maybe not but still).

What Are They?

A marker interface is an empty interface (no methods or properties) that is used to identify classes that implement it belong to a special group. Some might argue that this is a code smell, but in certain situations they can be the best solution for constraining types.

What Are They?

Magic numbers are numbers in code that appear to be arbitrary, but actually serve a purpose. They are commonly described as an anti-pattern as they diminish code quality, and are “referred to as breaking one of the oldest rules of programming, dating back to the COBOL, FORTRAN and PL/1 manuals of the 1960s”. [1]

What are they?

While it may seem like nothing more than buzz words, dependency injection is a well known principle. In fact, you’ve likely used it yourself in the past and just didn’t know the technique had a name. Dependency injection can be thought of as passing a resource required by a class to the class through one of several means. While the class could instantiate a new instance of the resource itself, by using dependency injection we introduce an easier way to take advantage of dependency inversion.

Preface

Unit tests and integration tests are designed to serve two different purposes. They are not meant to substitute each other, and each type has a specific focus. However, developers tend to struggle to determine the border that seperates unit tests and integration tests as there is no set hard limit on either one.

Where I’ve Been, and Where I’m Heading

I took somewhat of an unplanned hiatus from working on No Mans Blocks. Initially, I took a break because I wanted to pursue writing a server for a Reddit clone. It wasn’t until about two months in that I realized just how over scoped the project was and how long it would take to finish. While I may not have much to show for this time, it did open my eyes up to some of the common software-architecture patterns, and how to utilize these patterns to better organize my projects. During my adventure I also picked up TypeScript and dived into the intriguing world of NodeJS.

It’s quite typical for a Domain Driven Design (DDD) project to need validation for it’s domain models. While it may be sufficient to solve this by adding an IsValid() method to each model, this can cause confusion for the developer by cluttering the model class, and/or by requiring the IsValid() method to be generalized that it covers a large range of validation rules for any situation that may arise. Let’s work with an example.