newlineDelimitedKeyValue

function newlineDelimitedKeyValue(obj, parentKey = '') {
    return Object.entries(obj)
        .map(([k, v]) => {
            if (typeof v === 'object') {
                return newlineDelimitedKeyValue(v, `${parentKey}${k}_`);
            }

            const kUpper = `${parentKey}${k}`.toUpperCase();
            return `${kUpper}=${v}`;
        })
        .join('\n');
}