x.js

// original: https://gist.github.com/qfox/5652198
// this would use dynamic variable access to store vars from different funcs
// dynamic prop access could very well kill optimizations though


// step1: change var
var $state = {};
function start(x){
  $state['start:foo'] = 0;

  if (x === 1) $state['start:foo'] = 1;
  else if (x === 2) $state['start:foo'] = 2;
  else if (x === 3) $state['start:foo'] = 3;
  else if (x === 4) $state['start:foo'] = 4;
  else $state['start:foo'] = 5; 

  return $state['start:foo'];
}

// step2: split up code branches
var $state = {};
function start(x){
  $state['start:foo'] = 0;

  if (x === 1) $state['start:foo'] = 1;
  else $start1(x);

  return $state['start:foo'];
}
function $start1(x){
  if (x === 2) $state['start:foo'] = 2;
  else $start2(x);
}
function $start2(x){
  if (x === 3) $state['start:foo'] = 3;
  else $start3(x);
}
function $start3(x){
  if (x === 4) $state['start:foo'] = 4;
  else $state['start:foo'] = 5; 
}