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

const fileType = '.mp3';
const folder = process.cwd();

function checkFile(folder, file) {

  return fs.lstatSync(path.resolve(folder, file)).isFile()
    && path.extname(file) === fileType;
}

function renameFile(file) {

  let newName = (file.includes('ma.mp3')) ? file.split('ma')[0] + fileType : file;

  console.log('file', file, newName);
  fs.renameSync(file, newName);
}

fs.readdirSync(folder)
  .filter(file => checkFile(folder, file))
  .forEach(file => renameFile(file));