Count words in file, order by highest count, limit by passed parameter

ordered-words.js

var word = /\b[a-zA-Z][a-zA-Z0-9\-']*\b/g;
var words = {};

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

function convert(str, amount) {

	str = fs.readFileSync(path.join(__dirname, str), 'utf8');
	while ((match = word.exec(str))) {
		var w = match[0].toLowerCase();
		words[w] = words[w] ? words[w] + 1 : 1;
	}
	var list = [];
	for (var found in words) {
		list[words[found]] = list[words[found]] || [];
		list[words[found]].push({'word': found, value: words[found]});
	}

	return list.filter(function (l) {
		return l != null;
	}).reduce(function (prev, cur) {
		return prev.concat(cur);
	},[]).slice(amount * -1).reverse();
}

console.log(convert(process.argv[2], process.argv[3]));