Workaround for lack of "tail call optimization" in JS

example.js

// Lack of tail call optimization in JS
var sum = function(x, y) {
  return y > 0 ? sum(x + 1, y - 1) :
         y < 0 ? sum(x - 1, y + 1) :
         x
}

sum(20, 100000) // => RangeError: Maximum call stack size exceeded

// Using workaround
var sum = tco(function(x, y) {
  return y > 0 ? sum(x + 1, y - 1) :
         y < 0 ? sum(x - 1, y + 1) :
         x
})
sum(20, 100000) // => 100020

tail-call-optimization.js

function tco(f) {
  /**
  Takes `f` function and returns one that may be used for tail recursive algorithms. 
  **/
  var active = false, value, accumulated, args
  return function accumulator() {
    accumulated = arguments
    if (!active) {
      active = true
      while (accumulated) {
        args = accumulated
        accumulated = null
        value = f.apply(this, args)
      }
      active = false
      return value
    }
  }
}