Renaming an image sequence with nodeJS & fs

main.js

var fs = require('fs');  

//That function list all the files in the directory.
//Loop all the file in the folder
//If the current object is a folder -> ignore it
//Else if the file name index of 'mairie' (the original image sequence file was named "mairie"+n, where n started at 200)
//rename it in "mairie"+i, to get an image sequence that begin at 0 and not 200
function getFiles (dir, files_){
    files_ = files_ || [];
    var files = fs.readdirSync(dir);
    for (var i in files){
        var name = dir + '/' + files[i];
        if( !fs.statSync(name).isDirectory() ){
        	if( name.indexOf('mairie') > -1 ){
            	files_.push(name);
            	fs.renameSync( name, dir + '/' + 'mairie' + i + '.png' );
        	}
        }
    }
    return files_;
}

console.log( getFiles('.') );