35 lines
1.6 KiB
JavaScript
35 lines
1.6 KiB
JavaScript
// we start with a selection of pitches that generally work okay together
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export const sopranoTones = ["B5", "A5", "G5", "F#5", "F5", "E5", "D5", "C5", "B4", "Bb4", "A4", "G4", "F#4", "F4", "E4"];
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export const altoTones = ["E5", "D5", "C5", "B4", "Bb4", "A4", "G4", "F#4", "F4", "E4", "D4", "C4", "B3", "Bb3", "A3", "G3"];
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export const tenorTones = ["G4", "F#4", "F4", "E4", "D4", "C4", "B3", "Bb3", "A3", "G3", "F3", "E3", "D3", "C3"];
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export const bassTones = ["C2", "D2", "E2", "F2", "G2", "A2", "Bb2", "B2", "C3", "D3", "E3", "F3", "G3"];
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// now we define some rules to allow for the program to follow so it can some basic tenets of music theory
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// we're going to include all pitches, so that it can use semitone-based pitch logic.
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// this is focused on base-12, something computers understand quite well
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const musicalPitches = ['A', "Bb", "B", "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#"];
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export const extractPitchset = (pitches) => {
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// 1) determine pitch set from given array of pitches
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let pitchset = [];
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for (let each of pitches) {
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// filters numbers from above tones
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const str = each;
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const regex = /[0-9]/g;
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const withoutNums = str.replace(regex, '');
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const pitchNumber = musicalPitches.indexOf(withoutNums);
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// ... so that they may be mapped onto numbers corresponding to the chromatic scale
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pitchset.push(pitchNumber);
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}
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// these are sorted from lowest to highest index (something like an interval vector)
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pitchset.sort((a,b) => a < b);
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console.log(pitchset);
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return pitchset;
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}
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// no tritones
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// no minor 2nds or major 7ths
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