kielbasa is a dependency free Reverse Polish Notation calculator written in JavaScript.
To run the code simply run npm start
To run the tests first run npm install then npm test
While working on this RPN calculator I wanted to challenge myself to make it completely free of dependencies (save for mocha as a test runner and sinon for spying/stubbing function calls). Requiring only a single command to run the application.
I really tried to lean into JavaScript's functional nature to make adding new operations and commands as easy as possible and to keep the code as clean and minimal as I could. I tried to adhere to the KISS principle as to not overcomplicate or overengineer it while also allowing for the possibility of additional room to expand the application.
I used a simple stack datatype for storing the operations similar to the first computer implementations of the notation
I used recursion to minimize the amount of overall code needed. The handleInput() function will handle both operations given on a single line e.g. 5 5 5 8 + + - and operations given sequentially. This allowed me to have one function handle both scenarios based on context requiring only a single function.
Had I had more time I would've come up with a better way of storing the operations rather than a global variable, given the time and scope I think this approach was sufficient.
I could have made the handleInput() function cleaner and try to avoid validating the inputs twice and not have as much logic branching.
Deciding to not use any dependencies added a few obstacles, primarily surrounding not having any type of transpiler which made testing a bit more difficult and requiring the use of ES5 modules as opposed to ES6.
Also given more time I would've had more thorough test coverage.