Make it a true shim

[walling]

If the JavaScript environment supports the String.prototype.normalize function, this library should use that and export is as the unorm functions (as fallback for code that expects it).

[phadej]

I'm not sure how to do this. It would be nice to still be able to use unorm implementation even browser has it's own.

[walling]

I thought something like this:

if (!String.prototype.normalize) {
  String.prototype.normalize = function() {
    // ... unorm implementation here ...

    return function(form) {
      // ...
    };
  };
}

var unorm = {
  nfc: function(str) { return ('' + str).normalize('NFC'); },
  // ...
};
// export unorm object to browser, CommonJS, AMD, etc.

But you're right: What if I want to use unorm implementation instead of the one supplied by the browser. I don't have a nice solution yet for this use case.

[Mouvedia]

What if I want to use unorm implementation instead of the one supplied by the browser.

It should work like this:

// this uses String.prototype.normalize if it's available
// but replaces it for any browser which has a partial implementation
import 'unorm';

// this uses unorm implementation
// granted you actually use the default export
import 'unorm' from 'unorm';