rational

Starting point#

This project’s starting point goes way back to the distant path, dating back before I became a web-developer. At that time I was learning the basics of python language (things did not go further than basics). Becoming familiar with OOP I have got the idea of implementing the rational numbers support. At that moment python provided built-in Fraction module, but the interface seemed to basic for me.

Quite possible considering the language, the problem, and existing module, I was reinventing the wheel. At that moment it should not be a problem, in my opinion. The task seemed to be possible for my level and it was really interesting for me.

The project was finished and I was pleased with the result. Thanks to the project I learned more about OOP and python itself. Obviously, the project was not published and was completely forgotten deep in file system of my laptop.

Second encounter#

After quite a while, as can be seen in most of my projects, I decided to come back to the project. There were some rationale behind this decision. At that moment I was on my way to become a web-developer and the language I was using to do the job was (what a surprise!) JavaScript, and I already had some experience of planning and deploying projects.

Most importantly, JavaScript do not have a rational numbers support. And I was thinking that it would be a nice idea to create a library for it. I could get some experience, refresh the knowledge of more or less simple math topic. And, maybe, just maybe if a library turned out to be good, the community may find it useful.

So, I have decided to implement a library, call it rational and publish it on npm.

The process#

The development process was quite pleasing and productive. I have already got the experience of package publishing and other stuff required to do the job.

Before the work I did some research, learned from existing libraries what does such a library should have under it’s belt to be competitive. After that the interface was planned and it was developed using TypeScript.

As a result, the zipped package was just a 2 kb in size, it seemed like a really good result considering the functionality was built in.

User input#

More or less most such a libraries has the same interface. You can create instances and make some operations. You can read what a rational can do in documentation. But I would like to highlight the flexibility of user input:

• (n?: int = 0, d?: int = 1) — integer numerator and denominator values as parameters;
• (input: [ n: int = 0, d?: int = 1 ]) — integer numerator and denominator values as an array;
• (input: { int?: number = 0, n: int, d?: int = 1 }) — integer numerator and denominator values and optional integer part as an object;
• (input: StringFraction) — a string in format of "{sign?}{numerator}/{sign?};
• (input: RepeatingDecimal) — a periodic continued fraction as an object;
• (input: StringRepeatingDecimal) — a string as periodic continued fraction in format of {sign?}{int?}.{non-repeating}?({repeating});
• (input: Degrees) — degree measure value as an object;
• (input: StringDegrees) — a degree measure string in format of {sign?}{degrees?}.{minutes'?}{seconds''?}.

What makes it even greater the same user input can be used in most methods where another rational instance would be required.

Summarizing#

The project itself cannot be considered something outstanding; any developer with a couple of years experience can easily write such a project. However, I was pleased with the result considering my self-criticism and attention to details.

The library is packed with types, the user input types are included for a developer, covered with unit tests, has a good documentation and a functionality covering all needs you may need working with rational numbers. In case a developer need something specific, library is naturally extendable and written using modern JavaScript syntax.

There are some limitations considering the Number data type. I was considering using BigInt instead, but I had doubts that people may need such an extreme values using this library and the performance dropped significantly (up to 10x).

There are some plans for this project to be a part of some other educational projects in future. The project itself is maintained and always is up to date.