ESM cannot load a module "synchronously" with a dynamic specifier. Until we have top-level await, I think we need a supported way to do it. Two use cases:

let env;
if (process.env.NODE_ENV === 'production') {
  env = require('./prod.js');
} else {
  env = require('./dev.js');
}

let canvas, hasCanvas;
try {
  canvas = require('canvas');
  hasCanvas = true;
} catch (e) {
  hasCanvas = false;
}

I can think of three solutions:

1. Explain in the documentation that one has to write the dynamic code in a commonJS module and import it.
2. Add import.meta.require
3. Add a builtin module that provides the require function (npm proposal)