Felix Roos a2ab2b9da5 build
2022-03-06 21:39:10 +01:00

69 lines
2.8 KiB
JavaScript

import {Note, Interval, Scale} from "../_snowpack/pkg/@tonaljs/tonal.js";
import {Pattern as _Pattern} from "../_snowpack/link/strudel.js";
import {mod, tokenizeNote} from "../_snowpack/link/util.js";
const Pattern = _Pattern;
export function scaleTranspose(scale, offset, note) {
let [tonic, scaleName] = Scale.tokenize(scale);
let {notes} = Scale.get(`${tonic} ${scaleName}`);
notes = notes.map((note2) => Note.get(note2).pc);
offset = Number(offset);
if (isNaN(offset)) {
throw new Error(`scale offset "${offset}" not a number`);
}
const {pc: fromPc, oct = 3} = Note.get(note);
const noteIndex = notes.indexOf(fromPc);
if (noteIndex === -1) {
throw new Error(`note "${note}" is not in scale "${scale}"`);
}
let i = noteIndex, o = oct, n = fromPc;
const direction = Math.sign(offset);
while (Math.abs(i - noteIndex) < Math.abs(offset)) {
i += direction;
const index = mod(i, notes.length);
if (direction < 0 && n[0] === "C") {
o += direction;
}
n = notes[index];
if (direction > 0 && n[0] === "C") {
o += direction;
}
}
return n + o;
}
Pattern.prototype._transpose = function(intervalOrSemitones) {
return this._withEvent((event) => {
const interval = !isNaN(Number(intervalOrSemitones)) ? Interval.fromSemitones(intervalOrSemitones) : String(intervalOrSemitones);
if (typeof event.value === "number") {
const semitones = typeof interval === "string" ? Interval.semitones(interval) || 0 : interval;
return event.withValue(() => event.value + semitones);
}
return event.withValue(() => Note.simplify(Note.transpose(event.value, interval)));
});
};
Pattern.prototype._scaleTranspose = function(offset) {
return this._withEvent((event) => {
if (!event.context.scale) {
throw new Error("can only use scaleTranspose after .scale");
}
if (typeof event.value !== "string") {
throw new Error("can only use scaleTranspose with notes");
}
return event.withValue(() => scaleTranspose(event.context.scale, Number(offset), event.value));
});
};
Pattern.prototype._scale = function(scale) {
return this._withEvent((event) => {
let note = event.value;
const asNumber = Number(note);
if (!isNaN(asNumber)) {
let [tonic, scaleName] = Scale.tokenize(scale);
const {pc, oct = 3} = Note.get(tonic);
note = scaleTranspose(pc + " " + scaleName, asNumber, pc + oct);
}
return event.withValue(() => note).setContext({...event.context, scale});
});
};
Pattern.prototype.define("transpose", (a, pat) => pat.transpose(a), {composable: true, patternified: true});
Pattern.prototype.define("scale", (a, pat) => pat.scale(a), {composable: true, patternified: true});
Pattern.prototype.define("scaleTranspose", (a, pat) => pat.scaleTranspose(a), {composable: true, patternified: true});