objectZip iterator for javascript

objectZip.js

var _ = require('underscore');

/**
 * functional zip() for JS objects
 *
 * Skips keys not present in both sides
 *
 * @param  a left object
 * @param  b right object
 * @param  f(key, aval, bval) iterator
 */
function objectZip(a, b, f) {
    _.each(a, function(v, k) {
        if (_.has(b, k)) f(k, v, b[k])
    })
}