text animation

A font drop dynamic effect. Follow Dope Motions to complete
The expression is as follows：
freq = 1;

decay = 25;

duration = 0.30;

retard = textIndex*thisComp.frameDuration*1;

t = time - (inPoint + retard);

startVal = [100,100,100];

endVal = [0,0,0];

if (t < duration){

linear(t,0,duration,startVal,endVal);

}else{

amp = (endVal - startVal)/duration;

w = freq*Math.PI*2;

endVal + amp*(Math.sin((t-duration)*w)/Math.exp(decay*(t-duration))/w);

}