moment-of-symmetry/dist/src/modes/index.js

Moment of Symmetry (MOS) musical scale generation and analysis for Javascript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.getDaughterPatterns = exports.getParentPattern = exports.getAllModes = exports.getModeInfo = void 0;
const names_1 = require("../names");
/**
 * Get information about a mode
 * @param pattern The MOS pattern
 * @param options Optional configuration
 * @returns Information about the mode
 */
function getModeInfo(pattern, options) {
    var _a, _b;
    const info = (_a = (0, names_1.tamnamsInfo)(pattern.pattern)) !== null && _a !== void 0 ? _a : {};
    const name = (_b = (0, names_1.modeName)(pattern.pattern, options === null || options === void 0 ? void 0 : options.extraNames)) !== null && _b !== void 0 ? _b : pattern.pattern;
    return {
        pattern: pattern.pattern,
        name,
        ...info,
    };
}
exports.getModeInfo = getModeInfo;
/**
 * Get all modes for a given pattern
 * @param pattern The MOS pattern
 * @param options Optional configuration
 * @returns Array of mode information
 */
function getAllModes(pattern, options) {
    var _a, _b;
    const modes = [];
    const patternStr = pattern.pattern;
    for (let i = 0; i < patternStr.length; i++) {
        const rotatedPattern = patternStr.slice(i) + patternStr.slice(0, i);
        const info = (_a = (0, names_1.tamnamsInfo)(rotatedPattern)) !== null && _a !== void 0 ? _a : {};
        const name = (_b = (0, names_1.modeName)(rotatedPattern, options === null || options === void 0 ? void 0 : options.extraNames)) !== null && _b !== void 0 ? _b : rotatedPattern;
        modes.push({
            pattern: rotatedPattern,
            name,
            ...info,
        });
    }
    return modes;
}
exports.getAllModes = getAllModes;
/**
 * Get the parent MOS pattern for a given pattern
 * @param pattern The MOS pattern to get the parent for
 * @returns The parent MOS pattern
 */
function getParentPattern(pattern) {
    const gcd = (a, b) => (b === 0 ? a : gcd(b, a % b));
    const periods = gcd(pattern.largeSteps, pattern.smallSteps);
    if (periods === 1) {
        throw new Error('Pattern has no parent (it is already a single-period MOS)');
    }
    const parentLargeSteps = pattern.largeSteps / periods;
    const parentSmallSteps = pattern.smallSteps / periods;
    return {
        pattern: 'L'.repeat(parentLargeSteps) + 's'.repeat(parentSmallSteps),
        largeSteps: parentLargeSteps,
        smallSteps: parentSmallSteps,
        periods: 1,
    };
}
exports.getParentPattern = getParentPattern;
/**
 * Get the daughter MOS pattern(s) for a given pattern
 * @param pattern The MOS pattern to get the daughter(s) for
 * @returns Array of daughter MOS patterns
 */
function getDaughterPatterns(pattern) {
    const daughters = [];
    // For each possible number of periods
    for (let periods = 2; periods <= Math.min(pattern.largeSteps, pattern.smallSteps); periods++) {
        if (pattern.largeSteps % periods === 0 &&
            pattern.smallSteps % periods === 0) {
            const daughterLargeSteps = pattern.largeSteps / periods;
            const daughterSmallSteps = pattern.smallSteps / periods;
            daughters.push({
                pattern: 'L'.repeat(daughterLargeSteps) + 's'.repeat(daughterSmallSteps),
                largeSteps: daughterLargeSteps,
                smallSteps: daughterSmallSteps,
                periods: 1,
            });
        }
    }
    return daughters;
}
exports.getDaughterPatterns = getDaughterPatterns;
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