char-slop/chordpad.vibed.software

git clone https://git.t4t.associates/char-slop/chordpad.vibed.software

Charlotte Sominitial commit3c7bc6e2026-09-30

import { assertEquals } from "@std/assert";
import { type HookpadChord, type HookpadSong, readSection } from "./hookpad.ts";
import { theoryTabPath, theoryTabProject } from "./theorytab.ts";

const chord = (fields: Partial<HookpadChord>): HookpadChord => ({
  beat: 1,
  duration: 4,
  root: 1,
  type: 5,
  inversion: 0,
  applied: 0,
  adds: [],
  omits: [],
  alterations: [],
  suspensions: [],
  borrowed: null,
  pedal: null,
  substitutions: [],
  isRest: false,
  ...fields,
});

const song = (fields: Partial<HookpadSong>): HookpadSong => ({
  keys: [{ beat: 1, scale: "major", tonic: "C" }],
  meters: [{ beat: 1, numBeats: 4, beatUnit: 1 }],
  tempos: [{ beat: 1, bpm: 100 }],
  chords: [],
  notes: [],
  endBeat: 5,
  ...fields,
});

const symbols = (chords: Partial<HookpadChord>[], key = { scale: "major", tonic: "C" }) =>
  readSection(song({ keys: [{ beat: 1, ...key }], chords: chords.map(chord) })).chords.map(
    c => c.symbol,
  );

Deno.test("hookpad chords as symbols", () => {
  assertEquals(
    symbols([
      { root: 1 },
      { root: 6 },
      { root: 5, type: 7 },
      { root: 5, type: 7, inversion: 1 },
      { root: 1, inversion: 2 },
      { root: 2, type: 7, inversion: 3 },
      { root: 7, type: 7 },
      { root: 4, type: 9 },
      { root: 5, suspensions: [4] },
      { root: 1, adds: [9] },
      { root: 1, omits: [3] },
      { root: 5, type: 7, alterations: ["b9"] },
    ]),
    ["C", "Am", "G7", "G7/B", "C/G", "Dm7/C", "Bm7b5", "Fmaj9", "Gsus4", "Cadd9", "C5", "G7b9"],
  );
});

Deno.test("borrowed and secondary chords", () => {
  assertEquals(
    symbols([
      { root: 7, borrowed: "minor" },
      { root: 4, borrowed: "minor" },
      { root: 6, borrowed: "minor", type: 7 },
      { root: 2, borrowed: "phrygian" },
      // stored as the target degree, with the secondary function in `applied`
      { root: 6, applied: 5 },
      { root: 5, applied: 5, type: 7 },
      { root: 2, applied: 7, type: 7 },
      // a custom scale, in semitones above the tonic
      { root: 3, borrowed: [0, 2, 3, 5, 7, 8, 10] },
    ]),
    ["Bb", "Fm", "Abmaj7", "Db", "E", "D7", "C#dim7", "Eb"],
  );
});

Deno.test("minor keys count degrees in the minor scale", () => {
  assertEquals(
    symbols([{ root: 1 }, { root: 3 }, { root: 5 }, { root: 5, borrowed: "harmonicMinor" }], {
      scale: "minor",
      tonic: "A",
    }),
    ["Am", "C", "Em", "E"],
  );
});

Deno.test("theoretical keys and double accidentals get their everyday spellings", () => {
  assertEquals(symbols([{ root: 1 }, { root: 5 }], { scale: "major", tonic: "D#" }), [
    "Eb",
    "Bb",
  ]);
  assertEquals(symbols([{ root: 1 }, { root: 6 }], { scale: "minor", tonic: "Db" }), [
    "C#m",
    "A",
  ]);
  // V6/vi in B major: D♯ with F𝄪 in the bass
  const secondary = symbols([{ root: 6, applied: 5, inversion: 1 }], {
    scale: "major",
    tonic: "B",
  });
  assertEquals(secondary, ["D#/G"]);
  const key = readSection(song({ keys: [{ beat: 1, scale: "minor", tonic: "Gb" }] })).key;
  assertEquals(key, { tonic: "F#", scale: "minor" });
});

Deno.test("melody pitches: octave 0 starts at the tonic above middle C", () => {
  const read = readSection(
    song({
      keys: [{ beat: 1, scale: "major", tonic: "A" }],
      notes: [
        { beat: 1, duration: 1, sd: "1", octave: 0, isRest: false },
        { beat: 2, duration: 1, sd: "5", octave: -1, isRest: false },
        { beat: 3, duration: 0.5, sd: "b3", octave: 0, isRest: false },
        { beat: 3.5, duration: 0.5, sd: "1", octave: 0, isRest: true },
        { beat: 4, duration: 1, sd: "#4", octave: 1, isRest: false },
      ],
    }),
  );
  assertEquals(read.notes, [
    { start: 0, dur: 1, pitch: 69 },
    { start: 1, dur: 1, pitch: 64 },
    { start: 2, dur: 0.5, pitch: 72 },
    { start: 3, dur: 1, pitch: 87 },
  ]);
});

Deno.test("a key change applies from its beat on", () => {
  const read = readSection(
    song({
      keys: [
        { beat: 1, scale: "major", tonic: "C" },
        { beat: 5, scale: "major", tonic: "D" },
      ],
      chords: [chord({ root: 1, beat: 1 }), chord({ root: 1, beat: 5 })],
      notes: [{ beat: 5, duration: 1, sd: "1", octave: 0, isRest: false }],
      endBeat: 9,
    }),
  );
  assertEquals(
    read.chords.map(c => [c.start, c.symbol]),
    [
      [0, "C"],
      [4, "D"],
    ],
  );
  assertEquals(read.notes[0].pitch, 62);
});

Deno.test("a theorytab becomes a project with its sections end to end, on bar lines", () => {
  const verse = song({
    keys: [{ beat: 1, scale: "minor", tonic: "D#" }],
    tempos: [{ beat: 1, bpm: 92.4 }],
    chords: [chord({ root: 1, duration: 4 }), chord({ root: 6, beat: 5, duration: 2 })],
    endBeat: 7, // a bar and a half: the chorus should still start on bar 3
  });
  const chorus = song({
    keys: [{ beat: 1, scale: "minor", tonic: "D#" }],
    chords: [chord({ root: 4 })],
    notes: [{ beat: 1, duration: 2, sd: "5", octave: 0, isRest: false }],
  });
  const p = theoryTabProject({
    title: "Some Song – Someone",
    sections: [
      { name: "verse", song: verse },
      { name: "empty", song: song({}) },
      { name: "chorus", song: chorus },
    ],
  });
  assertEquals(
    [p.name, p.bpm, p.key],
    ["Some Song – Someone", 92, { tonic: "D#", mode: "aeolian" }],
  );
  const [chords, melody] = p.tracks;
  assertEquals(chords.kind === "chords" && chords.chords.map(c => [c.start, c.dur, c.symbol]), [
    [0, 4, "D#m"],
    [4, 2, "B"],
    [8, 4, "G#m"],
  ]);
  assertEquals(melody.kind === "notes" && melody.notes.map(n => [n.start, n.pitch]), [[8, 70]]);
});

Deno.test("theorytab links", () => {
  const path = "/theorytab/view/the-beatles/let-it-be";
  assertEquals(
    theoryTabPath("https://www.hooktheory.com/theorytab/view/the-beatles/let-it-be"),
    path,
  );
  assertEquals(
    theoryTabPath("  hooktheory.com/theorytab/view/the-beatles/let-it-be"),
    undefined,
  );
  assertEquals(
    theoryTabPath("https://hooktheory.com/theorytab/view/the-beatles/let-it-be/chorus?x#y"),
    path,
  );
  assertEquals(
    theoryTabPath("https://example.com/theorytab/view/the-beatles/let-it-be"),
    undefined,
  );
  assertEquals(
    theoryTabPath("https://www.hooktheory.com/theorytab/artist/the-beatles"),
    undefined,
  );
});