urbit-browser-manager/extension/popup/popup.js

const browser = require("webextension-polyfill");

console.log("popup.js running");

const getLocalStorage = browser.storage.sync.get();

document.querySelector("#options").addEventListener("click", () => {
  browser.runtime.openOptionsPage();
});

getLocalStorage.then((result) => {
  const loggedInSelector = document.querySelector("#loggedInMsg");
  if (result.credentials && result.credentials.urbitId && result.credentials.urbitCode) {
    loggedInSelector.textContent = `Hi, ~${result.credentials.urbitId}`;
  } else {
    loggedInSelector.textContent = "Not logged in";
  }
});