Do you have a datasheet or product description of the actual string of WS2811s that you are planning on using?
@Kolban started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Do you have a datasheet or product description of the actual string of WS2811s that you are planning on using?