A super-duper-tiny LOC counter (with no external dependencies).

loc.js

#!/usr/bin/env node

'use strict';

/**
 *
 * A super-duper-tiny LOC counter (with no external dependencies).
 *
 *    Usage: loc "path" "extension-to-filter"
 *
 *    Example: loc "/home/akoenig/projects/a" "js"
 * 
 * @author André König ([email protected])
 * @version 0.1.0
 *
 */

var fs       = require('fs'),
    path     = require('path'),
    readline = require('readline');

/**
 * Recursive directory walker.
 *
 */
function walker (dir, extension, next) {
    var results = [],
        opens;

    if (!extension) {
        return next(new Error('Please define a file extension.'))
    }

    fs.readdir(dir, function (err, list) {
        if (err) {
            return next(err);
        }

        opens = list.length;

        if (!opens) {
            return next(null, results);
        }

        list.forEach(function (file) {
            file = dir + '/' + file;

            fs.stat(file, function(err, stat) {
                if (stat && stat.isDirectory()) {
                    walker(file, extension, function(err, res) {
                        results = results.concat(res);

                        if (!--opens) {
                            return next(null, results);
                        }
                    });
            } else {

                if (('.' + extension) === path.extname(file)) {

                    results.push(file);
                }

                if (!--opens) {
                    return next(null, results);
                }
            }
      });
    });
  });
}

module.exports = (function () {
    var directory = process.argv[2],
        extension = process.argv[3];

    if (!directory || !extension) {
        return console.error('Please define the necessary arguments\n\n    Usage: loc "path" "extension-to-filter"\n    Example: loc "/home/akoenig/projects/a" "js"');
    }

    walker(directory, extension, function onWalked (err, files) {
        var i = 0,
            len = files.length;

        function next () {
            var file = files.pop(),
                reader;

            if (file) {
                reader = readline.createInterface({
                    input: fs.createReadStream(file),
                    output: process.stdout,
                    terminal: false
                });

                reader.on('line', function(line) {
                    i = i + 1;
                });

                reader.on('close', next);
            } else {
                console.log('Summary: %d LOC in %d files', i, len);
            }
        }

        next();
    });
})();

package.json

{
    "name": "loc",
    "version": "0.1.0",
    "author": "André König ([email protected])",
    "bin": {
        "loc": "./loc.js"
    }
}