const { JSDOM, VirtualConsole } = require("jsdom");

const { window } = new JSDOM(undefined, {
  virtualConsole: new VirtualConsole(),
});
const { document } = window;

const div = document.createElement("div");
document.body.appendChild(div);

div.style.setProperty("border-color", "gray");

console.log(window.getComputedStyle(div).getPropertyValue("border-color"));