WS2812B LED strip and ESP8266 shows wrong colors

@user85573, thank you very much for you effort... (and mending the t0... copy/paste shoving code around tripped me... and still is. May be does not matter because the times as captured by you show already a nice difference...) My intensions for timing instrumentation are never to include console out... but I missed that part too. The correct code for 2(b) would be more along these lines:

Variation 2(b))

// V2b - flash an 8 LED neopixel array in a rainbow pattern
var neo = require("neopixel");
var led_count = 8;
var neoPin = NodeMCU.D4;
var rgb = new Uint8ClampedArray(led_count * 3);
var len = rgb.length;
var m = 127;
var r = 0.1324*m;
var g = 0.1654*m;
var b = 0.1*m;
var pos = 0;
function getPattern() {
  var t0 = getTime();
  pos++;
  for (var i=0; i<len;) {
    rgb[i++] = m + Math.sin((i+pos)*r;
    rgb[i++] = m + Math.sin((i+pos)*g;
    rgb[i++] = m + Math.sin((i+pos)*b;
  }
  console.log(getTime() - t0);
  return rgb;
}
function bow() {
  neo.write(neoPin, getPattern());
}
function onInit() {
  setInterval(bow,200); // may need to change to allow console to write
}
setTimeout(onInit, 1000);

I was missing line 13 completely and line 20 I should have made to read:

t0 = getTime() - t0;
console.log(t0);

But anyway, thanks for timing it for me.

Conclusion is that doing some optimization to prevent (source code) interpreter to do some things all over again saved about 20..25%. The numbers also show that the write is practically neglectable compared to the trigonometric calculations.