currency-exchange-api

All basic tools included and configured:

• TypeScript 4.0
• ESLint with some initial rules recommendation
• Jest for fast unit testing and code coverage
• Type definitions for Node.js and Jest
• Prettier to enforce consistent code style
• YARN for common operations
• GraphQl query language

Implemented an LRU Cache algorithm.

Getting Started

This project is intended to be used with the latest Active LTS release of Node.js.

Try it live: https://currency-exchange-api-v1.herokuapp.com/quote (GraphQl request)

Clone repository

To clone the repository use the following commands:

git clone git@github.com:matass/currency-exchange-api.git

Configuration

Default configuration file – .env

API_URL=api.exchangeratesapi.io
PORT=4000
CAPACITY=2
CURRENCIES=USD,EUR,GBP,ILS

Server

This project is dockerised. Edit .env file and run docker-compose up --build. It will run application in development mode.

Running app with Yarn:

yarn install
yarn build
yarn server 

Visit http://0.0.0.0:4000/quote to enter GraphiQL interface

Available Scripts

• server - run server
• clean - remove coverage data, Jest cache and transpiled files,
• build - transpile TypeScript to ES6,
• build:watch - interactive watch mode to automatically transpile source files,
• lint - lint source files and tests,
• test - run tests,
• test:watch - interactive watch mode to automatically re-run tests

GraphQl request

{
  quote(
    quote_currency: "USD"
    base_currency: "EUR"
    base_amount: 1500
  ){
    exchange_rate
    quote_amount
  }
}

cURL request

curl 'http://localhost:4000/quote?' \
  -X GET \
  -H 'Content-Type: application/json' \
  --data-binary '{"query":"{ quote ( quote_currency: \"USD\" base_currency: \"EUR\" base_amount: 1){exchange_rate quote_amount}}"}'

Writing tests

Writing unit tests in TypeScript can sometimes be troublesome and confusing. Especially when mocking dependencies and using spies.

This is optional, but if you want to learn how to write JavaScript tests for TypeScript modules.

Todo

• API Versioning

License

Licensed under the MIT.