avasconcelos114 / crypto-exchange

Crypto Exchange App

Thoughts

Sockets? not this time :(

I initially tried to create an implementation of each socket API from the exchanges, but had to drop the idea as it became apparent that managing 4 wildly different websockets with their own set of intervals and PING/PONG messages would require far too much time to be able to finish the entire set of requirements within the 3 day deadline

TypeScript?

Dealing with varying payloads from different API servers, and state managed with Redux reminded me why TypeScript is usually well worth the time invested with adding type safety on component props, API responses, and redux state.

However due to time constraints I had to opt not to use it for this code task

Validation

A process that validates whether each pair (BTC/USD, etc) is acceptable is sorely needed, as in its current iteration still accepts a completely invalid pair (aoedjae/oeaaef)

The process I think is most ideal would:

1. fetch a list of valid items from a backend server
2. show suggestions for valid choices as the user types on the input
3. Trigger the history.push() event only by the user clicking on a value already established as valid by the server

Route Changes

While the original requirements needed the http://url.com/{cryptocurrency_pair}/details URL to open a modal with latest trade history, we needed a way to know which exchange's data needed to be shown on screen. As a result I had to change the path parameters to /{cryptocurrency_pair}/{exchange}/details

CORS Issues

Bitfinex seems to want us to only connect to their API from another server, and has a Access-Control-Allow-Origin header set up which prevented us from accessing it normally from a browser. This required me to set up a local proxy on setupProxy.js so that local development would not be hindered.

Ideally we would have a node servers that takes in requests for a given trading pair / exchange, and returns data in a uniform format so that we would not require as much business logic to parse through responses.

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Requirements

Our goal is to create a simple web app that provides quick access to the current market prices of selected cryptocurrency pairs.

Targeted Exchanges with open APIs:

Binance - https://www.binance.com/en

Bitfinex - https://www.bitfinex.com/

Huobi - https://www.huobi.com/en-us/

Kraken - https://www.kraken.com/

The initial screen should consist of search functionality where the user can type the cryptocurrency pair of interest, for example - BTC/USD, BTC/USDT, ETH/USD, etc.

The application should crawl the data from all the exchanges listed above and visualise the current market price for each of them, e.g. Binance: 1 BTC = $40,000 USDT.

The application should consider the case the pair is not supported on selected exchange and communicate it properly in the interface.

The user should be able to:

• Search for a particular cryptocurrency exchange pair.
• Get the results and being able to sort them by price.
• Click on the price to view additional historical information about the last few trades (sell/buy) on that exchange, visualized in a modal window.
• Initiate the search functionality by opening the application through url containing the pair string: http://url.com/{cryptocurrency_pair}/, and opening the detail view on a pair by http://url.com/{cryptocurrency_pair}/details

UX, styling and attention to detail is up to you.

Bonus: While staying on the results page, update the market prices automatically in a reasonable time intervals.

What can be used:

• ReactJS
• Redux
• Webpack
• Any other library considered necessary

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Please upload your complete source code to a GitHub repo.

How we will test your code:

1. git clone
2. yarn && yarn start