start packaging

packages/xen/tune.mjs

@@ -0,0 +1,16 @@
+import Tune from './tunejs.js';
+import { Pattern } from '../core/strudel.mjs';
+
+Pattern.prototype._tune = function (scale, tonic = 220) {
+  const tune = new Tune();
+  if (!tune.isValidScale(scale)) {
+    throw new Error('not a valid tune.js scale name: "' + scale + '". See http://abbernie.github.io/tune/scales.html');
+  }
+  tune.loadScale(scale);
+  tune.tonicize(tonic);
+  return this._asNumber()._withEvent((event) => {
+    return event.withValue(() => tune.note(event.value)).setContext({ ...event.context, type: 'frequency' });
+  });
+};
+
+Pattern.prototype.define('tune', (scale, pat) => pat.tune(scale), { composable: true, patternified: true });