Jaikoz: rename file from metadata (compilation rename mask)

jaikoz-rename-file-compilation.js

/* -*-javascript-*-
 * Rename file from Metadata (Compilation rename mask)
 */
function pad(number, length) {
    if (number == '') { return ''; }
    var str = '' + number;
    while (str.length < length) {
        str = '0' + str;
    }
    return str;
}

function ifnotempty(value, sep) {
    return value.length > 0 ? value + sep : '';
}

function ifnotempty2(value1, value2, sep) {
    return value1.length > 0 ? value1 + sep : value2.length > 0 ? value2 + sep : '';
}

ifnotempty(pad(trackno, 2), ' - ') + ifnotempty(artist, ' - ') + title;