learnyounode/exercises/filtered_ls/solution/solution.js

Learn You The Node.js For Much Win! An intro to Node.js via a set of self-guided workshops.

var fs = require('fs')
var path = require('path')

fs.readdir(process.argv[2], function (err, list) {
  list.forEach(function (file) {
    if (path.extname(file) === '.' + process.argv[3])
      console.log(file)
  })
})