Design decisions

Used TypeScript instead of JavaScript because it is more maintainable.
Input the transactions from the CSV file and filter them depending on the user's input(s)
External inputs such as the CLI input date, the CSV data, and the Crypto Compare API response are validated with Zod. This provides true type safety.
To fetch as less as possible, the USD exchange rates are fetched only once for each unique token.
Used maps instead of objects because they are easier to set and get. Map is also iterable and fast.
Added Jest tests for each utility file because tests improve maintainability.
Added linting with ESLint because it helps find and fix code problems.
Added code formatting with Prettier because it enforces the same code format across the entire project.
Used pnpm instead of npm because it is faster and stricter.

How to use

npm i -g pnpm
pnpm i
pnpm build
Create a .env file and add CRYPTO_COMPARE_API_KEY
Run pnpm start or pnpm start --token <token> or pnpm start --date <date> or add both options