Ping is not a recognized export about node-minecraft-protocol

[rom1504]

Please use commonjs

[PondWader]

You are importing commonjs with ESM, node.js only supports importing commonjs exports as a default export when imported in an ESModule.

[Opisek]

Alright, I see. I created this issue, because I could import everything else the ESM way with no issues, so ping was the outlier to me.

[extremeheat]

The import syntax does not do destructuring, despite the similar syntax. It instead looks up objects against the module's ESM exports list. The technical reason for this is that ESM export/import lookups are done statically in the parse step before the program is run. This is so browsers can asynchronously load all the dependencies for a page without needing to synchronously run the code and fetch the deps one by one. With CommonJS only an object is exported (or a function/variable under the module.export variable), that's translated to the default export in ESM. Now setting aside CommonJS translation, the default export in ESM is intended for when you want to export an anonymous function or variable from a file, which would be named by the caller. Like the error message says you would need to use a different import syntax for destructuring:

import pkg from 'minecraft-protocol'; // pkg gets the default export variable and assigns it to pkg
const { ping } = pkg; // this actually does destructuring to get the ping function from pkg object

When you do a "namespace import" like:

import * as pkg from 'pkg'

You are binding all the ESM exports into pkg, including the default one.

So why can you do import {x, y, z} from 'pkg' or import * as pkg from 'pkg'; pkg.x sometimes as opposed to using the default object in Node.js? That's because Node.js added a compatibility feature to try and export all the CommonJS exports as ESM exports. But again since all the ESM import/export are done statically, that compatibility feature works without running the code. So it can only use static analysis to try and make the CommonJS module look like an ESM one before the code is ran. You can see this for yourself by adding a console.log to the top of node_modules/minecraft-protocol/index.js and checking that error on importing ping -- no log will be made. If the static translator gets stuck, it will give up trying to promote things inside module.export to ESM exports, so you must use the default export object and destructure at runtime.

[Opisek]

I see. Thank you for the comprehensive explanation and apologies for my confusion!