HaiBV / 2b-boilerplate

Usage

Please clone the git repo, then runs the 2 following command sequentially.

Copy the transactions.csv in data folder.

npm i
npm start

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Approach

First, I read the csv file the get the transaction of tokens. Here I am using a library csv-parse to parse the transaction.

Because the timestamp order by DESC to I read the transactions from the end. For each transaction, I get transactionType, token and amount and accumulate their amount to the tokens variable.

Finally, I call an API to obtain the exchange rates compared from token to USD, then do the multiplication to convert the final amounts to USD.

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Design decisions

1. Setting Configuration variables

CRYPTO_CURRENCY_URL = "https://min-api.cryptocompare.com/data/pricemulti"

These are used to get exchange rates from multiple tokens to multiple currencies.

2. Error Handling

If there are no transactions on log file

We console the error

No token transactions on the logs.

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Structure of the source code

├── LICENSE
├── package.json
├── README.md
├── data
│  └── transactions.csv
├── src
│  ├── portfolio.js
│  └── utils.js
└── index.js

portfolio.js

This is where we implement functionalities in commands.

utils.js

This file contains the utilization functions.

getExchangeRate: Get the current exchange rate of any cryptocurrency in any other currency that you need.

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Question 1 - Programming

We're looking at your programming ability. It must not only work, it should be maintainable.

Let us assume you are a crypto investor. You have made transactions over a period of time which is logged in a CSV file at the data directory. Write a command line program that returns the latest portfolio value per token in USD

The program should be ran like this

npm run start

On running, it should return the latest portfolio value per token in USD

The CSV file has the following columns

• timestamp: Integer number of seconds since the Epoch
• transaction_type: Either a DEPOSIT or a WITHDRAWAL
• token: The token symbol
• amount: The amount transacted

Portfolio means the balance of the token where you need to add deposits and subtract withdrawals. You may obtain the exchange rates from cryptocompare where the API is free. You should write it in Node.js as our main stack is in Javascript/Typescript and we need to assess your proficiency.

Submission

Please take no more than 2 hours to finish. We do not track time, hence you can start and end at your own time. Your answers should comprise of the following

• Source code that you used for deriving the results
• README that explains various design decisions that you took.

Commit your answers in a private Github repository(it's free), please do not fork as other candidates will see your answers. Add Zan(liangzan), Ben(BenPropine) as collaborators then inform us that it is done at [e-mail], [e-mail].