Run a queue of functions sequentially.
npm install runq
runq = require("runq"); runq() .add(function(cb, a) { cb(null, a + 1); }) .add(function(cb, a) { cb(null, a + 1); }) .run(function(err, r) { // all done if(err) { // ... } else { console.log(a); // 3 } }, 1)