Cash-machine-problem NPM

cash-machine-problem

a simple micro-library that develops a solution that simulates the delivery of notes when a client does a withdraw in a cash machine.

Requirements

Always deliver the lowest number of possible notes
It’s possible to get the amount requested with available notes
The client balance is infinite
Amount of notes is infinite
Available notes 100,00, 50,00, 20,00, 10,00 $

Examples

Entry: 30.00 Result: 20.00, 10.00
Entry: 80.00 Result: 50.00, 20.00, 10.00
Entry: 125.00 Result: throw NoteUnavailableException
Entry: -130.00 Result: throw InvalidArgumentException
Entry: NULL Result: Empty Set

Install

npm i cash-machine-problem

Install locally

git clone https://github.com/paschalidi/cash-machine-problem.git
cd cash-machine-problem
npm i

Watch Tests

npm run test

Run tests once

npm run test:single

Usage

import calculateNotes from 'cash-machine-problem'

// Returns an array of the lowest number of possible notes
calculateNotes(100)
//=> [100, 0, 0, 0]

calculateNotes(120)
//=> [100, 0, 20, 0]

calculateNotes(130)
//=> [100, 0, 20, 10]

...

API

calculateNotes(integer)

Returns an array of of 4 integers in the following format [x1, x2, x3, x4].

x1 represents the amount of $100.00 that the cash machine should return

x2 represents the amount of $50.00 that the cash machine should return

x3 represents the amount of $20.00 that the cash machine should return

x4 represents the amount of $10.00 that the cash machine should return

Architectural Notes

Automated releases with `semantic-release-cli`

We set up smeantic-release-cli with semantic-release-cli setup
We chose Travis CI for continuous integration
We added an extra script to travis.yml so that tests run before every release. This way if tests dont pass then the release wont happen
We also added ghooks so that before every commit tests run and any test fail commit wont take place.

Testing

For testing we chose mocha and chai. There reason is the clean api they provide.

Code structure

src/index.js contains the implementation of the calculateNotes()
exports a default function so that the end user can be able to specify the name of it herself/himself.
The tests are also included in the src directory.

Build process

When travis builds the lib the following comand is being executed babel --copy-files --out-dir dist --ignore *.test.js src. babel will copy all the files from the src directory into the dist directory and will also convert them to es5 so that it is executable from every browser or node version needed. Also the test files are ignored so that the end user wont have them in her/his node_modules directory.
before every build the following script will run rimraf dist.
This will remove the dist directory and will run the command for every operating system (Windows, iOS or Linux).
More info about rimraf here.