Applying some ideas of http://matt.might.net/articles/by-example-continuation-passing-style/

continuation-passing-style.js

// Continuation Passing Style (CPS)
console.log('CPS factorial') 
const CPS_fact = (n, callback = log) => {
  console.log('CPS_fact push stack when n = '+ n)  
  if(n === 0) {
    //console.log(`then we call callback$${n}(1)`)
    callback(1)// executed when n is 0  
  } else {
    //console.log(`when n = ${n} then callback$${n - 1} = e => callback$${n}(e * ${n})`)
    CPS_fact(n - 1, r => { 
      //console.log(`then we call callback$${n}(${r * n})`)
      callback(r * n); 
    })// thanks to closure™
  }  
  console.log('CPS_fact pop stack when n = '+ n)  
}
CPS_fact(
  3,
  r => console.log(
    r + 
    ' We get the result first' + 
    ' and then we exit the stack'
  )
)

console.log('')
console.log('Simple factorial')
const factorial = n => {
  console.log('factorial push stack when n = '+ n)  
  const res = n === 0 ? 1 : n * factorial(n - 1)
  console.log('factorial pop stack when n = '+ n)  
  return res
}
console.log(
  factorial(3) + 
  ' We have to wait to exit the stack' + 
  ' to use the result'
)

// convenient default
function log(e) {
  console.log(e)
}

// Uncomment the three lines in CPS factorial for more detail.