a duplexing stream country counter (honestly I have no idea what this does)

hideous.js

var duplexer = require('duplexer');
var through = require('through');

module.exports = function (counter) {
    var counts = {}
    return duplexer(through(function write (row) {
    	counts[row.country] = (counts[row.country] || 0) + 1
    }, function end () {
    	counter.setCounts(counts)
    }), counter)
}