Fullstack Developer Task Implementation

This pull request fulfills the requirements outlined in the Fullstack Developer Task, involving the creation of a backend GraphQL API to fetch and cache exchange rates, and a frontend interface to display the data.

Backend Implementation

1. GraphQL Query for Exchange Rates

   • Added a getExchangeRates query to fetch exchange rates from the Czech National Bank.
   • The query returns the following fields:
     • country
     • currency
     • amount
     • code
     • rate

2. Data Caching

   • Implemented a caching mechanism using PostgreSQL with a 5-minute lifetime:
     • Cached data is read from the database if valid.
     • Expired cache triggers fetching, storing, and returning updated data from the Czech National Bank.

Frontend Implementation

1. Exchange Rates Table

   • Developed a web page using React and TypeScript to display exchange rates in a table format.
   • Used MUI Data Grid for:
     • Client-side filtering.
     • Pagination and sorting.

2. Last Fetch Time

   • Included a section to display the time elapsed since the last fetch, providing visibility into the cache status.

Screenshot

image