gistfile1.js

var Flow = require('make-flow')
// definition
var app = Flow()
.def('sum1', function (done) {
  add(1, 2, done)
})
.def('sum2', function (done) {
  add(3, 4, done)
})
.def('result', function (sum1, sum2, done) {
  add(sum1, sum2, done)
})

// usage
app.run().eval('result', function (err, result) {
  // do something with result
})