learn you node filter list of file names

filterlist.js

var fs = require('fs');

String.prototype.endsWith = function (suffix) {
    return this.indexOf(suffix, this.length - suffix.length) !== -1;
};

var dir = process.argv[2];
var postFix = process.argv[3];

fs.readdir(dir, function (err, list) {

    list.filter(function (fileName) {
        return fileName.endsWith("." + postFix);
    }).forEach(function (fileName) {
            console.log(fileName);
        });
});