Applying a colour variable to a Rectangle with Figma API?

  const allVariables = await figma.variables.getLocalVariablesAsync("COLOR");
  const mainVar = allVariables.find(v => v.name === "Some/Random/color");
  if (!mainVar) {
    console.error("Color variable 'main' not found.");
    return;
  } else {
    console.error("Color found -> ", mainVar);
  } 

 const circle = figma.createRectangle();
  circle.resize(64, 64);
  circle.cornerRadius = 50;
  circle.name = "Color Circle";
  circle.x = component.width - circle.width - 10;
  circle.y = (component.height - circle.height) / 2;
  circle.fills = []; 

Hi all!

I’m struggling to apply a variable from my list to the Rectangle I created with the pluginAPI. All solutions that I come across tend to pull the value of the variable out and apply it to the circle/rectangle. However, I lose the relationship with the list of variables that appear in my fill area/widget. Surely I should be able to apply the ‘key’ of the variable and figma will take the value an apply it to my circle/rectangle automagically? I’ve been stuck on this for a while now and it’s quite frustrating to find anything that points me in the right direction. 

Thanks!

Mark