ecmascript5

import console; module util { print: (m){console.log(m);}; }; export class Foo { use util; init: (v){this.v = isFinite(v) ? v:0, this;}; print: (m){util.print(m), this;}; class self.Bar { extends Foo; '+': (v){isFinite(v) ? v:this.v;}; print: (v){super(this + v);}; }; }; fb = new Foo.Bar(); fb.print(10);

Usage no npm install needed!

<script type="module">
  import ecmascript5 from 'https://cdn.skypack.dev/ecmascript5';
</script>

README

import console; module util { print: (m){console.log(m);}; }; export class Foo { use util; init: (v){this.v = isFinite(v) ? v:0, this;}; print: (m){util.print(m), this;}; class self.Bar { extends Foo; '+': (v){isFinite(v) ? v:this.v;}; print: (v){super(this + v);}; }; }; fb = new Foo.Bar(); fb.print(10);