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import { MajorScale, MinorScale, chromaticScale } from "./scale.mjs";
function scaleFrom(tonic, scale) {
switch (scale) {
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('scale'));
['tonic', 'second', 'third', 'fourth', 'fifth', 'sixth', 'seventh'].forEach((c, i) => {
Array.from(form.getElementsByClassName(c)).forEach(elt => elt.innerText = scale[i]);
});
// todo: memoize this or put it in the scales module.
const allScales = chromaticScale.flatMap(tonic => {
return [MajorScale(tonic), MinorScale(tonic)];
})
const availableScales =
allScales.reduce((acc, s, i) => {
const suffix = i % 2 == 0 ? '' : 'min';
if (scale.includes(s.tonic) && scale.includes(s.third) && scale.includes(s.fifth)) {
return acc.concat(`${s.tonic}${suffix}`);
}
return acc;
}, []);
Array.from(form.getElementsByClassName('chords')).forEach(list => {
const items = availableScales.map(s => {
const elt = document.createElement('li');
elt.innerText = s;
return elt;
});
list.replaceChildren();
items.forEach(item => list.appendChild(item));
});
}
function handleFormChanged(e) {
formChanged(e.target.form);
}
export default function KeyPicker(form) {
console.debug('KeyPicker()', form);
form.onchange = handleFormChanged;
formChanged(form);
}
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