Getting up and running

For the purposes of this exercise only npm was catered for in terms of lock files

Total time spent was around 3-5 hours including this document

Please spend the time reading the readme

By running $ npm run test you should see the output

Options considered for the example

• seed a database with the text files and interact with the database (complexity in setup for reviewer - docker needed etc)
• read the text and manually build data structures (more fun)
• front-end only with create-react-app allowing user to upload the files and see a sexy UI (probably not sticking to the brief for output, would have probably been the fastest solution)
• do micro-services (would be cool but have personal time constraints and complexity of setup for reviewer - docker needed etc)
  • file-reader service
  • data-formatter service
  • db-seeder service
  • get-feed service
  • web service

Additional Notes

• Hand coded (with some googling help) and tried to use as little helper libraries as possible when interacting with the data lodash > union was used.
• Testing was done using jest and supertest
• Some of the data manipulation to get to the end result could be way simpler but wanted to show thought in data transformation - example, there was no need to format the tweets file to be [{ user: 'A', msg: 'my message' }], a simple startsWith(`${user}> `) could have been done eliminating additional loops and functions
• If a SQL DB was to be used character limits for tweets would have been considered for table schemas, 4 tables would be created, one for users, one joining table for relationships in following, one for tweets one for relationships between users and tweets

Assumptions

• the text files provided could grow - so used a createReadStream as opposed to the readFileSync although it might not impact performance on such a small file
• no CI config was required (one can be supplied if needed)
• no logging to external services like splunk or sentry etc was required
• no caching was required (caching can be added - for the purposes of this I would ave used memcached but love redis)
• no guards required for routes - only helmet was added to show thought towards protection
• self-healing would be handled by environment such as kubernetes etc
• https would be handled by the environment
• output to node console and response to browser would be okay

Accessing the server

Depending on the PORT you have chosen the application should be available on http://localhost:2001 by default

Installation

$ npm install or $ yarn

Environment Variables

Rename .env.sample to .env

or you can run $ NODE_ENV=production PORT=3000 npm run start

Running Tests

$ npm run test or $ yarn test

Development

$ npm run dev or $ yarn dev

Production

$ npm run start or $ yarn start