music-visualizer/scripts/make-demo.mjs

import fs from 'node:fs';
import path from 'node:path';

const divisions = 4;
const typeFor = (d) =>
  ({16: 'whole', 8: 'half', 4: 'quarter', 2: 'eighth', 1: '16th'})[d] ?? 'quarter';

let xml = `<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE score-partwise PUBLIC "-//Recordare//DTD MusicXML 4.0 Partwise//EN" "http://www.musicxml.org/dtds/partwise.dtd">
<score-partwise version="4.0">
  <work><work-title>Morning Window</work-title></work>
  <identification>
    <creator type="composer">Demo · Original</creator>
    <encoding><software>music-visualizer demo generator</software></encoding>
  </identification>
  <part-list><score-part id="P1"><part-name>Piano</part-name></score-part></part-list>
  <part id="P1">
`;

function note(step, octave, duration, opts = {}) {
  const {chord = false, staff = 1, voice = '1', tie, grace = false} = opts;
  const parts = [];
  if (grace) parts.push('<grace/>');
  if (chord) parts.push('<chord/>');
  parts.push(`<pitch><step>${step}</step><octave>${octave}</octave></pitch>`);
  if (!grace) parts.push(`<duration>${duration}</duration>`);
  if (tie === 'start') parts.push('<tie type="start"/>');
  if (tie === 'stop') parts.push('<tie type="stop"/>');
  parts.push(`<voice>${voice}</voice>`);
  if (!grace) parts.push(`<type>${typeFor(duration)}</type>`);
  else parts.push('<type>eighth</type>');
  if (tie) {
    parts.push(`<notations><tied type="${tie}"/></notations>`);
  }
  parts.push(`<staff>${staff}</staff>`);
  return `      <note>${parts.join('')}</note>\n`;
}

function rest(duration, opts = {}) {
  const {staff = 1, voice = '1'} = opts;
  return `      <note><rest/><duration>${duration}</duration><voice>${voice}</voice><type>${typeFor(duration)}</type><staff>${staff}</staff></note>\n`;
}

function leftArpeggio(notes) {
  // 8 eighth notes = 16 divisions
  let out = '';
  for (const [step, octave] of notes) {
    out += note(step, octave, 2, {staff: 2, voice: '5'});
  }
  return out;
}

const measures = [
  // 1
  {
    right:
      note('C', 5, 4) +
      note('E', 5, 2) +
      note('G', 5, 2) +
      note('A', 5, 4) +
      note('G', 5, 4),
    left: leftArpeggio([
      ['C', 3], ['G', 3], ['E', 4], ['G', 3],
      ['C', 3], ['G', 3], ['E', 4], ['G', 3],
    ]),
  },
  // 2
  {
    right:
      note('F', 5, 4) +
      note('E', 5, 2) +
      note('D', 5, 2) +
      note('C', 5, 8) +
      note('E', 5, 8, {chord: true}) +
      note('G', 5, 8, {chord: true}),
    left: leftArpeggio([
      ['F', 3], ['C', 4], ['A', 3], ['C', 4],
      ['F', 3], ['C', 4], ['A', 3], ['C', 4],
    ]),
  },
  // 3
  {
    right:
      rest(4) +
      note('G', 5, 2) +
      note('A', 5, 2) +
      note('G', 5, 4) +
      note('E', 5, 4),
    left: leftArpeggio([
      ['G', 3], ['D', 4], ['B', 3], ['D', 4],
      ['G', 3], ['D', 4], ['B', 3], ['D', 4],
    ]),
  },
  // 4
  {
    right:
      note('D', 5, 4) +
      note('E', 5, 4) +
      note('C', 5, 8),
    left: leftArpeggio([
      ['C', 3], ['G', 3], ['E', 4], ['G', 3],
      ['C', 3], ['G', 3], ['E', 4], ['G', 3],
    ]),
  },
  // 5
  {
    right:
      note('E', 5, 4) +
      note('G', 5, 2) +
      note('A', 5, 2) +
      note('C', 6, 4) +
      note('B', 5, 4),
    left: leftArpeggio([
      ['A', 3], ['E', 4], ['C', 4], ['E', 4],
      ['A', 3], ['E', 4], ['C', 4], ['E', 4],
    ]),
  },
  // 6
  {
    right:
      note('A', 5, 4) +
      note('G', 5, 2) +
      note('E', 5, 2) +
      note('D', 5, 4) +
      note('E', 5, 4),
    left: leftArpeggio([
      ['F', 3], ['C', 4], ['A', 3], ['C', 4],
      ['F', 3], ['C', 4], ['A', 3], ['C', 4],
    ]),
  },
  // 7
  {
    right:
      note('G', 5, 4) +
      note('E', 5, 2) +
      note('D', 5, 2) +
      note('C', 5, 8),
    left: leftArpeggio([
      ['G', 3], ['D', 4], ['B', 3], ['D', 4],
      ['G', 3], ['D', 4], ['B', 3], ['D', 4],
    ]),
  },
  // 8
  {
    right:
      note('D', 5, 4) +
      note('E', 5, 2) +
      note('F', 5, 2) +
      note('G', 5, 8, {tie: 'start'}),
    left: leftArpeggio([
      ['C', 3], ['G', 3], ['E', 4], ['G', 3],
      ['C', 3], ['G', 3], ['E', 4], ['G', 3],
    ]),
  },
  // 9
  {
    right:
      note('G', 5, 8, {tie: 'stop'}) +
      note('A', 5, 4) +
      note('G', 5, 4),
    left: leftArpeggio([
      ['A', 3], ['E', 4], ['C', 4], ['E', 4],
      ['A', 3], ['E', 4], ['C', 4], ['E', 4],
    ]),
  },
  // 10
  {
    right:
      note('A', 5, 2, {grace: true}) +
      note('G', 5, 4) +
      note('E', 5, 4) +
      note('D', 5, 8),
    left: leftArpeggio([
      ['F', 3], ['C', 4], ['A', 3], ['C', 4],
      ['F', 3], ['C', 4], ['A', 3], ['C', 4],
    ]),
  },
  // 11
  {
    right:
      note('E', 5, 4) +
      note('G', 5, 2) +
      note('A', 5, 2) +
      note('C', 6, 8),
    left: leftArpeggio([
      ['G', 3], ['D', 4], ['B', 3], ['D', 4],
      ['G', 3], ['D', 4], ['B', 3], ['D', 4],
    ]),
  },
  // 12
  {
    right:
      note('B', 5, 4) +
      note('A', 5, 4) +
      note('G', 5, 8),
    left: leftArpeggio([
      ['C', 3], ['G', 3], ['E', 4], ['G', 3],
      ['C', 3], ['G', 3], ['E', 4], ['G', 3],
    ]),
  },
  // 13
  {
    right:
      note('C', 6, 4) +
      note('B', 5, 2) +
      note('A', 5, 2) +
      note('G', 5, 4) +
      note('E', 5, 4),
    left: leftArpeggio([
      ['A', 3], ['E', 4], ['C', 4], ['E', 4],
      ['A', 3], ['E', 4], ['C', 4], ['E', 4],
    ]),
  },
  // 14
  {
    right:
      note('F', 5, 4) +
      note('E', 5, 2) +
      note('D', 5, 2) +
      note('C', 5, 8),
    left: leftArpeggio([
      ['F', 3], ['C', 4], ['A', 3], ['C', 4],
      ['F', 3], ['C', 4], ['A', 3], ['C', 4],
    ]),
  },
  // 15
  {
    right:
      note('D', 5, 4) +
      note('E', 5, 4) +
      note('G', 5, 8),
    left: leftArpeggio([
      ['G', 3], ['D', 4], ['B', 3], ['D', 4],
      ['G', 3], ['D', 4], ['B', 3], ['D', 4],
    ]),
  },
  // 16
  {
    right:
      note('C', 5, 16) +
      note('E', 5, 16, {chord: true}) +
      note('G', 5, 16, {chord: true}),
    left:
      note('C', 3, 16, {staff: 2, voice: '5'}) +
      note('E', 3, 16, {staff: 2, voice: '5', chord: true}) +
      note('G', 3, 16, {staff: 2, voice: '5', chord: true}),
  },
];

measures.forEach((measure, index) => {
  const number = index + 1;
  xml += `    <measure number="${number}">\n`;
  if (number === 1) {
    xml += `      <attributes>
        <divisions>${divisions}</divisions>
        <key><fifths>0</fifths></key>
        <time><beats>4</beats><beat-type>4</beat-type></time>
        <staves>2</staves>
        <clef number="1"><sign>G</sign><line>2</line></clef>
        <clef number="2"><sign>F</sign><line>4</line></clef>
      </attributes>
      <direction placement="above">
        <direction-type><metronome><beat-unit>quarter</beat-unit><per-minute>96</per-minute></metronome></direction-type>
        <sound tempo="96"/>
      </direction>
      <barline location="left"><repeat direction="forward"/></barline>
`;
  }
  if (number === 9) {
    xml += `      <direction placement="above">
        <direction-type><metronome><beat-unit>quarter</beat-unit><per-minute>104</per-minute></metronome></direction-type>
        <sound tempo="104"/>
      </direction>
`;
  }
  xml += measure.right;
  xml += `      <backup><duration>16</duration></backup>\n`;
  xml += measure.left;
  if (number === 4) {
    xml += `      <barline location="right"><repeat direction="backward" times="2"/></barline>\n`;
  }
  xml += `    </measure>\n`;
});

xml += `  </part>
</score-partwise>
`;

const out = path.resolve('public/demo/demo.musicxml');
fs.mkdirSync(path.dirname(out), {recursive: true});
fs.writeFileSync(out, xml, 'utf8');
console.log(`Wrote ${out} (${xml.length} bytes, ${measures.length} measures)`);