kickjunior

A command line version of Kickstarter built with the latest version of Node.js v5.4.1 (works with stable versions of Node v0.12 or newer). The application was built following specified requirements and is using an in-memory data store.

Installation

$ git clone https://github.com/natachaS/kickjunior.git
$ cd kickjunior/
$ npm install
$ node kickjunior.js

If you would like to run a suite of unit and integration tests you can run :

$ npm test

How does it work ?

Commands implemented:

KickJunior> project <project_name> <target_amount> : Starts a new project with a target amount

KickJunior> back <given_name> <project_name> <credit_card> <backing_amount> : Makes a pledge for a project with a valid credit card number

KickJunior> backer <given_name> : Lists the projects backed by a specific user

KickJunior> list <project_name> : Lists all backers for a specific project

Architectural thoughts

I really enjoyed working on this project! I chose Node.js because I had never built a REPL using Node before (but built a few using Ruby during my time at Flatiron). I initially used a module called Vorpal (based on Ruby's commander gem) but quickly realized it had its limitations, for example it was not checking the total number of arguments. So I rebuilt the project without it.

The in-memory data store has no data persistence. If persistence is desired we could still still use this simple data store by serializing updates out to a JSON file, or we could look at more robust solution based on redis, mongo or a more traditional database. The in-memory data store needs to lookup pledges by both project and backer, which required creating multiple indices. To help preserve data integrity, each pledge is stored only once, and indices refer to them via a unique id (RFC-compliant uuid, generated by the node-uuid module).

As a basic security measure, credit cards are stored as MD5 hashes instead of plain text. Card hashes are stored in a map to optimize the check if a credit card was already used by another user:

  cards: {
    '2893u23h23092830923adfadfa092': 'arya',
    '49834938498394839483984938493493': 'tywin'
  };

Future iterations: Add a database, build a web client, and of course logging, stats and health monitoring!