FunctionalEuler

FunctionalEuler.js

#!/sw/bin/js

function euler(firstPoint) {
   print("Curr is:" + firstPoint)
   function inner(passedPoint) {
      var prevAsOuter = passedPoint
      return function(currInner) {
         print("\nPrev was:" + prevAsOuter)
         print("Curr is:" + currInner)
         //Rewrite the fn yet again so prev will be stored 4 next time 
         euler = inner(currInner);
      }
   }
   //Rewrite the fn so that initial conditions are not repeated again
   euler = inner(firstPoint)
}

//Test Suite
euler(1);   //Output --> "Curr is:1"

euler(2);   //Output --> "Prev was:1"
            //           "Curr is:2"

euler(3);   //Output --> "Prev was:2"
            //           "Curr is:3"

euler(4);   //Output --> "Prev was:3"
            //           "Curr is:4"

euler(5);   //Output --> "Prev was:4"
            //           "Curr is:5"

If you wanted to make a nice curve between a series of points on an svg canvas, you could do a piece-wise continuous regression based upon the last 2 or 3 datums, instead of storing them all and doing a regression on all the points at the end.