Crypto portfolio tracker

Overview

This is a portfolio tracker that fetches transaction data from a CSV and exchange rates from Cryptocompare API and uses the data to to return computed values. The code is written using TypeScript and Node.JS with Express.

Approach

I executed a strategy that involved a streaming approach for processing the CSV data. This was accomplished by partitioning the data into manageable chunks and temporarily storing it in a buffer. The objective of this technique was to safeguard against potential code failures that could arise from attempting to load the entire data set into memory, as the size of the CSV file is substantial and could result in memory exhaustion. Additionally, we are executing computations on each data row incrementally while the data is being streamed, allowing us to perform the necessary processing in real-time.

Getting started

You can set up this project on your local computer using the following steps:

• Run git clone <repository> to clone this project to your local computer
• Open the root directory and run npm install
• Paste your CSV file into the root directory and make sure to name it transactions.csv
• Run npm run dev from the project directory to start the server.
• The server will run on localhost: 3000
• I have included my API key in the .env file for testing purposes but it is not a best practice to commit your .env file.

Once the server is running you can start making requests. You will see the logs on your terminal.

Endpoints

The server is written using express and each endpoint is configured to have a single function. You can use Postman to send requests to your server. Kindly note:

• The endpoints provided will only process JSON data.

• Make sure the Content-Type in your headers is set to application/json

localhost:3000/token

This endpoint accepts a GET request which will call a function to process the CSV data and return the latest portfolio value for all the tokens.

localhost:3000/token/latest

This endpoint accepts a POST request with a token value in the JSON object. This endpoint will call a function to process the CSV data and return the latest portfolio value for a specific token. Example of a valid JSON object: { "token": "ETH" }

localhost:3000/token/date

This endpoint accepts a POST request with a token and date value in the JSON object. The date value MUST follow the dd/MM/yyyy format. This endpoint will call a function to process the CSV data and return the latest portfolio value for a specific token up to a specified date. Example of a valid JSON object: { "token": "ETH", "date":"10/08/2022" }

localhost:3000/date

This endpoint accepts a POST request with a date value in the JSON object. The date value MUST follow the dd/MM/yyyy format. This endpoint will call a function to process the CSV data and return the latest portfolio value for all the tokens up to a specified date. Example of a valid JSON object: { "date":"10/08/2022" }