ES6 NodeJS script to process world cup data for group tournament scoring analysis. Blog: http://www.thebhwgroup.com/blog/2014/09/bi-nodejs-couchdb-mapreduce

process.js

"use strict;";

var co = require('co');
var u = require('underscore');
var fs = require('co-fs');
var printf = require('printf');
var moment = require('moment');
var forEach = require('co-foreach');
var nano = require('nano')('http://localhost:5984');
var couch = require('co-nano')(nano);

co(function * () {

	var re = /(\w{3})\/(\d{1,2})\s+\d+:\d+\s+(\w+)\s+(\d+)-(\d+)\s+(.*)\s+\@/g;
	var result = [];

	//read the finals
	var file = yield fs.readFile('./final.txt', 'utf8');
	while( (matches = re.exec(file)) !== null ){
		result.push({
			date: moment(printf("%s %d, 2014", matches[1], matches[2])).toDate(),
			home: matches[3].trim(),
			away: matches[6].trim(),
			home_score: parseInt(matches[4]),
			away_score: parseInt(matches[5]),
			finish: 3
		});
	}

	//read the cup
	file = yield fs.readFile('./cup.txt', 'utf8');
	while( (matches = re.exec(file)) !== null ){
		result.push({
			date: moment(printf("%s %d, 2014", matches[1], matches[2])).toDate(),
			home: matches[3].trim(),
			away: matches[6].trim(),
			home_score: parseInt(matches[4]),
			away_score: parseInt(matches[5]),
			finish: 2
		});
	}

	//read an entire directory of qualifiers...
	re = /(\w{3})\/(\d{1,2})\s+(\d{4})\s+(\w+)\s+(\d+)\-(\d+)\s+(.*)\s+\@/g;
	var files = yield fs.readdir('./quals/quals/2014--brazil/quali/');
	for( var i = 0; i < files.length; i++ ){
		file = yield fs.readFile('./quals/quals/2014--brazil/quali/' + files[i], 'utf8');
		while( (matches = re.exec(file)) !== null ){
			result.push({
				date: moment(printf("%s %d, %d", matches[1], matches[2], matches[3])).toDate(),
				home: matches[4].trim(),
				away: matches[7].trim(),
				home_score: parseInt(matches[5]),
				away_score: parseInt(matches[6]),
				finish: 1
			});
		}
	}

	//get a list of the unique teams, both home and away
	var teams = u.sortBy(u.uniq(u.union(u.pluck(result, 'home'), u.pluck(result, 'away'))), function(s){ return s;});
	var final_results = [];

	u.each(teams, function(team){
		//Map the home and away result to a strucutre we can aggregate
		var team_result = u.map(result, function(game){
			if( game.home === team ){
				return {
					team: team,
					goals_for: game.home_score,
					goals_against: game.away_score,
					win: game.home_score > game.away_score,
					loss: game.away_score > game.home_score,
					draw: game.home_score === game.away_score,
					finish: game.finish
				};
			} else if( game.away === team){
				return {
					team: team,
					goals_for: game.away_score,
					goals_against: game.home_score,
					win: game.home_score < game.away_score,
					loss: game.away_score < game.home_score,
					draw: game.home_score === game.away_score,
					finish: game.finish
				};
			} else {
				return null;
			}
		});

		var state = {
			team: team,
			goals_for: 0,
			goals_against: 0,
			win: 0,
			loss: 0,
			draw: 0,
			points: 0,
			goal_diff: 0,
			games: 0,
			finish: 0
		};

		//reduce the home and away results to tally the team's result
		var team_final = u.reduce(team_result, function(memo, res){
			if( res === null ){
				return memo;
			} else {
				memo.goals_for += res.goals_for || 0;
				memo.goals_against += res.goals_against || 0;
				memo.win += res.win === true ? 1 : 0;
				memo.loss += res.loss === true ? 1 : 0;
				memo.draw += res.draw === true ? 1 : 0;
				memo.points += Math.min(3, res.goals_for || 0) + (res.win === true ? 1 : 0 ) * 3 + (res.draw === true ? 1 : 0 );
				memo.goal_diff += (res.goals_for || 0) - (res.goals_against || 0 );
				memo.games += 1;
				memo.finish = Math.max(memo.finish, res.finish);

				return memo;
			}
		}, state);

		//fix-up our finish enumeration
		if( team_final.finish === 3 ){
			team_final.finish = 'Finals';
		} else if( team_final.finish === 2 ){
			team_final.finish = 'Cup';
		} else if ( team_final.finish === 1 ){
			team_final.finish = 'Qualifiers';
		}

		final_results.push(team_final);
	});
	
	//record our results in CouchDB
	var db = couch.use('world_cup_2014');

	forEach( final_results, function* (fres){
		var x = yield db.insert(fres, fres.team);
	}).then(function(){
		console.log('success');
	}, function(err){
		console.log(err);
	});

	console.log(JSON.stringify(final_results, null, 2));
})();

Interesting little program. You could have used the native ES5 functional javascript functions: map and reduce or the Lodash library which is a spinoff of Underscore but geared towards speed and performance.
I might try to implement the same kind of script but using Postgres as it supports Json and soon will have Jsonb in its 9.4 version.

Great suggestions on lodash or native V8 map/reduce functions for performance. This jsperf seems to imply that lodash may even be faster than V8's native map/reduce implementation, http://jsperf.com/fast-vs-lodash/12. lodash would be a drop-in replacement here from underscore.