Cannot import npm modules after converting ES5 require to ES6 import

I am trying to convert my npm package imports from ES5 (require) to ES6 (import...from) but I keep getting unexpected identifier errors. What should I be looking out for?

I have read through forums but honestly not sure what to try. I checked the documentation in MDN but none of those worked. Every single package has been tried individually but none of them work.

// changed version
import fs from 'fs';

// old imports
// const fs = require('fs')