I've a npm package with the following three files in the dist folder (generated by webpack):
Inside the package.json file I've declated the sample.js file as the main one: "main": "dist/sample.js",.
Now I wan't to use this package in another project. Did I need to import all three files? Or should all work fine with one import like import aFunction from 'package-name'?
If there aren't any other weird dependencies, and sample.js is actually the entrypoint of the library (i.e. either you do everything inside it, or you make all the needed exports from it), it should work fine just as you wrote, i.e. import aFunction from 'package-name'.
Btw, is sample.js minified? As far as I remember, starting with Webpack v4 it does the minification automatically for production builds. But you might still want to doublecheck (read here for more info).