How to use in non-module script?

[gweinfurther]

How can I use this without an import statement so I can use it in an existing non-module JS file?

[Senryoku]

It will mostly depend on your environment, are you using any bundler/build tools?

[gweinfurther]

I am using a home-grown bundler that combins and minimizes non-module script files. Other third party libraries are included in HTML script tags separately.

[Senryoku]

Mmh, I don't think separate script tags will work in this case, at least not without another module that exposes the exports (by adding them to a global object, or something similar).
Only solution I can think of right now is using a dynamic import (here from an npm install):

(async () => {
  const { compress, decompress } = await import('./node_modules/smol-string/dist/smol-string.js');
  
  const input = JSON.stringify({ imagine: "this is a large object" });
  
  const compressed = compress(input);
  const decompressed = decompress(compressed);
  console.log(compressed);
})();

This is will work directly in the browser, but might still depend on how your bundler works.