callback_promise.js

// Callback hell approach
function main() {
  console.log("hello from main")
  
  var name = "caius"

  sendHello(decorateName(name)) // <- smelly
}

function decorateName(name) {
  return `Prof. ${name}`
}

function sendHello(name) {
  console.log(`Why hello ${name}`)
}

main()


// Promises approach
new Promise(function(next, reject) {
  var name = "caius"
  next(name)
}).then(function(name) {
  new Promise(function(next, reject) {
    var decorated = `Prof. ${name}`
    next(decorated)
  })
}).then(function(name){
  console.log(`Why hello ${name}`)
})