When we talk about arrays we usually mean the vector of something – primitives, objects or even arrays. But there are a lot of situation when we need to carry extra information with our data. We can use nested arrays but it doesn’t cause that the specific item within the array will be easy to identify. To achieve it we should use custom keys. They provide easy access to any element of the array as long as we know the key corresponding with that value.
There are some reasons why we can use associative arrays instead of simple vectors, e.g. readability. Named keys are also more meaningful than numeric indexes. Instead of thinking about the whys, image the situation when we could use a hashmap. Let’s focus on how we can build the associative array from a vector.
If you frown after reading idempotence, don’t worry. Although this word sounds unusual it conceals a simple mathematics property. Needless to say, this characteristic has also a big meaning in Computer Science.
Idempotence operation is an operation that can be applied multiple times without changing the result beyond the initial application. It may sound difficult but after a couple of examples, the general concept will be obvious.
When I started my journey as a computer programmer I had written my code in a various way. I met some condition and I just put the correct statement regardless of the general concept or something more deeply. “It works, that’s it” – and the code base grew and grew in time. Thousands of written methods later I had discovered that a lot of these little pieces of logic could look better if I reverse some condition within them. Unconsciously, I’ve started following the rule which I had later called the “fail fast” rule.
I realized I hadn’t had the one way to check conditions within the single method. Sometimes I let execution if the expression was true. Another time I had waited for the false result to show the error message before the main part of the code was executing. In my head, I discovered various styles of checking conditions.
I remember how I was excited discovering how much frontend frameworks like AngularJS could make my work easier. Even though I was a strong backend-oriented programmer I decided to learn the concept of Angular. I dug into it at ease and I started using this tool in my daily work.
Since I changed my job I lost the opportunity to use frontend technologies regularly. However, I’m still fascinated about this part of software development and I follow trends and latest changes. Therefore AngularJS 1.x was officially abandoned I started looking for something new and fresh.
I didn’t look for a long time. When I first saw React library, I fall in love with it. I quickly caught the concept behind this tool, thanks to ubiquitous tutorials and examples. I read a lot about the flux pattern, redux, components but I didn’t chance to use them in something more ambitious than
<HelloWorld/> component. Till now.
Loop is the basic construction in each programming language. All repeatable operations are being done using loops. I think you know how the basic loops like while, do and for work and when you should use one of them. But are you sure? Maybe should you use array functions?
How many of your operations in a loop rely on building objects based on the value? Or selecting only a few items from the array using a predicate? Maybe you use array values to calculate something? Whatever you do, read why you should replacing basic loops by array operations.
ECMAScript 6 has an amazing feature called Arrow Function. It allows writing a function expression faster and smarter than traditional way (using function keyword). Worth to know, it’s not a one to one replacement for standard functions.
This kind of libraries (and frameworks) provide an another abstraction layer behind our code making the execution process more complex. It’s invisible until you’ll need to debug your code because of errors.
Do you use constants in your code? Probably a lot. Even if you don’t define your own is highly probable that you use some constants defined by other libraries or a language itself. Constants are very powerful unless you use it in the wrong way.