Batch js calls

batch-test.js

function randomTime() {
    return  Math.floor(Math.random() * 100) + 100;
}
 
function asyncFoo(_callback) {
    var err = false;
 
    setTimeout(function() {
        _callback({foo: "I am foo"}, err);
    }, randomTime());
}
 
function asyncBar(_callback) {
    var err = false;
 
    setTimeout(function() {
       _callback({bar: "I am bar"}, err);
    }, randomTime());
 
}
 
function done(results) {
    console.log("I am DONE", results); 
}
 
function main() {
    console.log("starting");
    var next = batch(done);
    
    asyncBar(next());
    asyncFoo(next());
}

main();

batch.js

function batch(done) {
    var pending  = 0;
    var finished = false;
    var results  = {};
    
    return function(){
        ++pending;
        return function(response, err){
            if (finished) return;
            
            if (err) {
                finished = true; 
                return done(err);
            } 
 
            for (var key in response) {
                results[key] = response[key]; 
            }
 
            console.log("pending calls: ", pending);
            --pending || done(results);
    };
  };
}