function to control an rgb led

There is something I missed. When the board starts, the led is off. Good. When I press the button, the led start directly and is not fading. The color jump from one to another one

function setLeds() {
  colFade += 0.05;
  if (colFade>=1) {
    colFade = 0;
    colFrom = colTo;
    var c = E.HSBtoRGB(Math.random(),1,1);
    colTo = [ (c&0xFF)/256, ((c>>8)&0xFF)/256, ((c>>16)&0xFF)/256 ];
  }
  analogWrite(LED1,colFrom[0]*(1-colFade) + colTo[0]*colFade, {soft:true});
  analogWrite(LED2,colFrom[1]*(1-colFade) + colTo[1]*colFade, {soft:true});
  analogWrite(LED3,colFrom[2]*(1-colFade) + colTo[2]*colFade, {soft:true});
}