gmf-js/lib/gmf.js

Generic Module Format (GMF) core library for Node.js

const fs = require("fs");
const path = require("path");

class GMF {
    constructor(folderPath) {
        this.folderPath = folderPath;
        this.gmfJson = null;
        this.samples = {};
        this.patterns = [];
    }

    load() {
        const gmfJsonPath = path.join(this.folderPath, "gmf.json");
        if (!fs.existsSync(gmfJsonPath)) throw new Error(`gmf.json not found in ${this.folderPath}`);

        this.gmfJson = JSON.parse(fs.readFileSync(gmfJsonPath, "utf8"));

        // Load samples
        const sampleFolder = path.join(this.folderPath, "samples");
        if (fs.existsSync(sampleFolder)) {
            fs.readdirSync(sampleFolder).forEach(file => {
                if (file.endsWith(".wav") || file.endsWith(".raw") || file.endsWith(".json")) {
                    this.samples[file] = path.join(sampleFolder, file);
                }
            });
        }

        // Load patterns
        const patternFolder = path.join(this.folderPath, "patterns");
        if (fs.existsSync(patternFolder)) {
            fs.readdirSync(patternFolder).forEach(file => {
                if (file.endsWith(".json")) {
                    const patternData = JSON.parse(fs.readFileSync(path.join(patternFolder, file), "utf8"));
                    this.patterns.push(patternData);
                }
            });
        }

        return this;
    }

    getInfo() {
        return this.gmfJson?.info || {};
    }

    getSamples() {
        return this.samples;
    }

    getPatterns() {
        return this.patterns;
    }
}

module.exports = GMF;