Trayt express.js coding challenge

To start the express server, run:

npm install

and then

npm start

Coding Challenge

Please read through this document before you start

Requirements

A simple express.js app already exists to save you some time. You should fork this repo and build on top of it.

You should allocate about 2 hours to work on this project. Although it is okay to exceed that time, we do encourage you to limit yourself. We appreciate that this is a significant investment of your time.

Testing the /recommendations endpoint

Please use this sample JWT eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJkdW1teSB0b2tlbiIsImlhdCI6MTY2OTQyNDM3NCwiZXhwIjoxNzAwOTYwMzc0LCJhdWQiOiJ3d3cuZXhhbXBsZS5jb20iLCJzdWIiOiJndXlAZXhhbXBsZS5jb20iLCJ1c2VySWQiOiI5YWFlYzFmYy1lYTEzLTQ3ODMtODFmOC1hOTk4YzFlMGQ2NDgifQ.BpUW_CQixSOtyIfwQ8OJmXS3_CRrJtZR7rtNjNBb1tE

Build a route to recommend movies for users based on user's rated movies

GET localhost:9000/recommendations Expected json response example

{
    "recommendation": {
        "favDirector": "Christopher Nolan",
        "favGenre": "Adventure",
        "byDirector": [
            {
                "id": "tt6723592",
                "name": "Tenet",
                "director": "Christopher Nolan",
                "genres": [ "Action", "Sci-Fi" ]
            },
            {
                "id": "tt5013056",
                "name": "Dunkirk",
                "director": "Christopher Nolan",
                "genres": [ "Action", "Drama", "History", "Thriller", "War" ]
            },
            // ...
        ],
        "byGenre": [
            {
                "id": "tt1345836",
                "name": "The Dark Knight Rises",
                "director": "Christopher Nolan",
                "genres": [ "Action", "Adventure" ]
            },
            {
                "id": "tt1375666",
                "name": "Inception",
                "director": "Christopher Nolan",
                "genres": [ "Action", "Adventure", "Sci-Fi", "Thriller" ]
            },
            // ...
        ]
    }
}

The route should have a middleware where it uses the user's Bearer Token to get the user's userId (which you will hard code to 9aaec1fc-ea13-4783-81f8-a998c1e0d648)
First you should get a list of movies a user has rated, ratedMovies. Using getRatedMovies(userId)
Figure out what is the name of a user's favorite director, favDirector. By counting the most popular director in ratedMovies list that have userRating larger or equal to 7 (1~10 scale)
Figure out what is a user's favorite genre, favGenre. By counting the most popular genre in ratedMovies list that have userRating larger or equal to 7 (1~10 scale)
Use favDirector to get a list of recommended movies made by this director (byDirector)
Use favGenre to get a list of recommended movies in the genre (byGenre)
Filter out movies in byDirector and byGenre that's already in the user's ratedMovies. (Because that means the user already watched it)
Use getSavedRecommendations(userId) to see if the user already have saved recommendation available. If it is the case, return saved recommendation. It not, get recommendation using the steps above and use saveRecommendations(userId, recommendation) to save the user's recommendation.

Helper functions

5 helper functions are available to mock the function of a database.

Get user's movie rating

A helper function getRatedMovies(userId) in helperFunctions.js is available to get a list of movies that user already rated. userRating have a scale of 1 to 10

// example output
[
  {
    id: 'tt0816692',
    name: 'Interstellar',
    director: 'Christopher Nolan',
    genres: [ 'Adventure', 'Drama', 'Sci-Fi', 'Thriller' ],
    userRating: 9
  },
  {
    id: 'tt0414993',
    name: 'The Fountain',
    director: 'Darren Aronofsky',
    genres: [ 'Drama', 'Mystery', 'Romance', 'Sci-Fi' ],
    userRating: 5
  },
  ...
]

Get Recommendation by director

A helper function getRecommendationByDirector(director) in helperFunctions.js is available to get a list of recommendated movies made by the same director

// getRecommendationByDirector('Christopher Nolan')
// example output
[
  {
    id: 'tt6723592',
    name: 'Tenet',
    director: 'Christopher Nolan',
    genres: [ 'Action', 'Sci-Fi' ]
  },
  {
    id: 'tt5013056',
    name: 'Dunkirk',
    director: 'Christopher Nolan',
    genres: [ 'Action', 'Drama', 'History', 'Thriller', 'War' ]
  },
  ...
]

Get Recommendation by genre

A helper function getRecommendationByGenre(genre) in helperFunctions.js is available to get a list of recommendation movies that's in the same genre

// getRecommendationByGenre('Adventure')
// example output
[
  {
    id: 'tt5104604',
    name: 'Isle of Dogs',
    director: 'Wes Anderson',
    genres: [ 'Animation', 'Adventure', 'Comedy', 'Drama', 'Fantasy', 'Sci-Fi']
  },
  {
    id: 'tt2278388',
    name: 'The Grand Budapest Hotel',
    director: 'Wes Anderson',
    genres: [ 'Adventure', 'Comedy', 'Crime' ]
  },
  ...
]

Save/get Recommendations

A helper function saveRecommendations(userId, recommendation) should be used to save the user's recommendation the first time user uses that route. (use's saved recommendation will be wiped after 10 seconds in this test. Realistically it should be something like a day or more)

A helper function getSavedRecommendations(userId) should be used to get user's recommendation if it is already saved.

Github branch

There are a couple of options on how to share the code with us:-

Please fork the repository on your local machine, make your changes and then commit to your private github repository. Once complete, please add the following github users to your private repo:

jcasner
harshnak
kgiberson

If you do not want to upload in you private repo, please email us the zip file of the code.

What we are looking for in this coding challenge

Able to understand requirements and build basic routes in express.js
Know how to deal with promises and use ES2017 async/await syntax
Know how to write easy to understand and easy to change code
Able to write efficient code that minimize response time
Able to make clean commits and make meaningful commit messages. (you should make small commits that shows how you progress in this project)

vudyaabhinav/trayt_express_challenge