Currency exchange

This is a js-responsive widget for currency exchange widget. The widget is composed of a web user interface backed by an API.

Installation

You need to write the following commands on the terminal screen so that you can run the project locally.

1. https://github.com/tekintopuz/exchange.git
2. cd exchange
3. npm install
4. npm start

The application is running on localhost.

Base usage on localhost.

How To Use

Place this script in your html. <script src="../static/js/exchange.js"></script>

API request interface

GET /quote

Query parameter Description

Parameter	Type	Description
baseCurrency	String	3 letters ISO currency code. Currency to convert from.
quoteCurrency	String	List dogs
baseAmount	Integer	The amount to convert in cents.Example: 100 (1 USD)

Example Url: http://localhost:3000/quote?baseCurrency=USD&quoteCurrency=EUR&baseAmount=100 Supported currencies are USD, EUR, GBP and ILS. API calculates the total amount expected in the quoteCurrency accordingly to the exchange rate provided by the 3rd party service.

Response body:

{
    "quoteAmount": 88.4,
    "exchangeRate": 0.884,
    "timestamp": 1638403201
}

API response interface

Response body: JSON with the following properties Property Description exchangeRate Decimal, the offered exchange rate. Up to 3 decimal digits. quoteAmount Integer, the expected amount in cents. You can choose the rounding policy.

Property	Description	Description
exchangeRate	Decimal	the offered exchange rate. Up to 3 decimal digits.
quoteAmount	Integer	the expected amount in cents.
baseAmount	Integer	The amount to convert in cents.Example: 100 (1 USD)
timestamp	Integer	unix timestamp in seconds

3rd Party Exchange Provider

Exchange rates are fetched from https://exchangerate-api.com. Issuing a GET request to the following URL will return the latest exchange rates for several currencies when the base currency USD: https://api.exchangerate-api.com/v4/latest/USD

Caching

For performance and cost reasons exchange rates are to be cached. Please implement a LRU Cache algorithm. For the purpose of the exercise use in memory storage.

Exchange UI widget

Layout

Rate section:

• Base currency dropdown
• Quote currency dropdown
• Base amount input

Results section:

• Conversion rate
• Expected amount

Functionality

• At first, only the rate section is visible.
• The user can select from Base and Quote currency dropdowns and enter Base amount.
• Once all fields are populated and valid, a request to get the quote is made.
• When results are returned, the results section is shown. The conversion rate and the expected amount are presented to the user. *The user can update any input in the rate section and get the updated results section with the new rate and amount.

Note: The UI is developed in simple way to work as compatible for both desktop and mobile.