npx ts-node index.ts your_input_file.csv > your_output_file.csv

ts-node index.ts your_input_file.csv > your_output_file.csv

tsc index.ts && node index.js your_input_file.csv > your_output_file.csv

You can run tests with: npm run test

(tests are using ts-node, so it's best to have that installed)

I always try to avoid 3rd party libraries, so whole thing is written in pure node. There are also couple things that could be improved, but as it's just a challenge I skipped some steps, like:

• any form of input validation -> program assumes input is always in proper structure, with same delimiters, quotes, file exists etc.
• program could be more user friendly with better error handling, error messages, retries etc.
• row processing is synchronous but if needed could be parallelized with worker threads
• buffer size is currently hardcoded to default value, but could be parsed from user params for user to control
• program could probably be half the code it is, but reading and maintaining it would be much harder, so I left it in more verbose manner