Can I Update A Js Variable's Property Dynamically From Another Variable?

I'm trying to update a property of a jS variable using the scroll velocity which I'm storing in another variable. This is my code thus far (scroll to the second code box as the fir

Solution 1:

You can take any object field reference using dot like

grainOptions.grainOpacity

Then you can redefine field value as using let variables. Update your scrollGlitch function:

function scrollGlitch(event) {
  var y = event.deltaY;
  var scaleY = y;
  var divider = 100;
  var sum = scaleY / divider;
  grainOptions.grainOpacity = sum;
}

Note. In JS you can take Object fields' value with 2 ways:

1. With saving reference on field to update it's own value. Ex:

grainOptions.grainOpacity.

2. Only for take value. Ex:

grainOptions['grainOpacity']