Dependency on deprecated Node "punycode" module

The project calls require('punycode'), using the Node punycode module which has been deprecated since v7 (2016). The Node docs now recommend using punycode.js in place of it.

This also means that when this library is used in a project using webpack, webpack must be manually configured to load punycode.js as a replacement for the punycode module because webpack since v5 (2020) no longer defaults to including shims for Node APIs like punycode.

It would be helpful if this library switched to using punycode.js instead of the Node punycode module.

[Macil]

I believe that part of the readme about browser support is just referring to that they started using ES2015isms like const and discontinued their UMD build which could work in pre-ES2015 browsers without a bundler. We’re using Punycode.js in browsers fine through Webpack right now, and Punycode.js’s ESM build even works directly as-is in browsers. (I think Punycode.js’s readme is misleadingly worded and I’ve sent a PR to fix that: https://github.com/mathiasbynens/punycode.js/pull/118.)

This library psl is already in CommonJS format and requires a bundler to be used within a browser, so adding a dependency on Punycode.js v2 would not cause a regression for people targeting (ES2015-supporting non-ancient) browsers specifically. But it would cause an issue for people not transpiling their code like with Babel and targeting ancient runtimes that don’t support ES6 features like const such as Rhino. It might be good for psl to do a major version update if it adds a dependency on Punycode.js v2 then.

[lupomontero]

Nice one @wegry 💪