Build from master fails due to ESM-only dependency "is-online"

[ldeld]

When building the project from the master branch I ran into the following issue:

A JavaScript error occurred in the main process
Uncaught Exception:
Error [ERR_REQUIRE_ESM]: require() of ES Module /tmp/.mount_BandcaAeC6lV/resources/app.asar/node_modules/is-online/index.js from /tmp/.mount_BandcaAeC6lV/resources/app.asar/src/main.js not supported.
Instead change the require of index.js in /tmp/.mount_BandcaAeC6lV/resources/app.asar/src/main.js to a dynamic import() which is available in all CommonJS modules.

Steps to reproduce:

• clone repo
• npm install
• npm start OR build and launch app image

This is because is-online is an ESM only package since version 9.

I found two possible fixes:

• Downgrade is-online to 8.5.1 (last CJS compatible version)
• Replace is-online with the esm2cjs version

I think this broke in this PR: https://github.com/themagiulio/bandcamp-desktop/pull/49/files , which upgraded is-online from 8.x to 10.0.
This was merged a few years ago though, so no idea why it still seems to work from most people.

I tested using node 16, 20 and 24 on Linux.