Function for generating permutations of a list.

permutations.js

// permutations(["c","a","t"])
function permutations(array){
  
  if (array.length === 0) return [[]];
  
  var perms = [];
  
  for(var i = 0; i < array.length; i++) {
    
    var copy = array.slice(0);
    var prefix = copy.splice(i,1);
    
    var rest = permutations(copy);
    
    for(var j = 0; j < rest.length ; j++) {
      perms.push(prefix.concat(rest[j])); 
    }
    
  }
  
  return perms;
}