modify note list when changing keys

1 files changed, 30 insertions, 0 deletions

diff --git a/key-picker.mjs b/key-picker.mjs
new file mode 100644
index 0000000..bd6482a
--- /dev/null
+++ b/key-picker.mjs
@@ -0,0 +1,30 @@
+import { MajorScale, MinorScale, chromaticScale } from "./scale.mjs";
+
+function scaleFrom(tonic, diatonic) {
+    switch (diatonic) {
+    case 'major':
+        return MajorScale(tonic);
+    case 'minor':
+        return MinorScale(tonic);
+    default:
+        throw new Error('how this happen')
+    }
+}
+
+function formChanged(form) {
+    const formData = new FormData(form);
+    const scale = scaleFrom(formData.get('tonic'), formData.get('diatonic'));
+    ['first', 'second', 'third', 'fourth', 'fifth', 'sixth', 'seventh'].forEach((c, i) => {
+        Array.from(form.getElementsByClassName(c)).forEach(elt => elt.innerText = scale[i]);
+    });
+}
+
+function handleFormChanged(e) {
+    formChanged(e.target.form);
+}
+
+export default function KeyPicker(form) {
+    console.debug('KeyPicker()', form);
+    form.onchange = handleFormChanged;
+    formChanged(form);
+}