Javascript - Cubic bezier to control points

I trying to optimize "SnapSVG path2curve" function with calculate control points.

I have alteative way, but it's very slow: '#Demo1': http://bl.ocks.org/mbostock/3916621

So, question is:

1. Path have like "M50,50 C50,10,35,90,55,15"

2. I converted it, but it looks like "[50, 50], [50, 10], [35, 90], [55, 15]".

3. I want control points like '#Demo1'. (It's uses getPointAtLength)

Why?

1. For shifting bezier

2. Change bezier points order to more good looking

Please help to make this, credits goes to that user.

Requirement: JavaScript, Simple (if possible).

Alteative search: Convert path to polygon