screen-width/util.js at main · TimoPot/screen-width · GitHub

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var injected = false;

function setStyle(sw) {
  // console.log(`setStyle`);
  sw.style.cssText = `display: block;
    position: fixed;
    top: 0px;
    right: 0px;
    height: 20px;
    padding: 2px 10px;
    background-color: yellow;
    color: black;
    z-index: 9999;
    font-size: smaller;`;
  sw.innerHTML = "" + window.innerWidth;
}

function createSWElement() {
  // console.log(`createSWElement`);
  let screenWidthElm = document.createElement("div");
  screenWidthElm.id = "screenWidth";
  setStyle(screenWidthElm);
  return screenWidthElm;
}

function getSWElement() {
  let screenWidthElm = document.querySelectorAll("#screenWidth")[0];
  if (screenWidthElm) {
    return screenWidthElm;
  }
}

function displayElement(screenWidthElm) {
  // console.log(`displayElement`);
  document.body.appendChild(screenWidthElm);
}

function init() {
  // console.log(`init`);
  let screenWidthElm = getSWElement();

  if (!screenWidthElm) {
    screenWidthElm = createSWElement();
    displayElement(screenWidthElm);
    addListeners();
  }
}

function finish() {
  // console.log(`finish`);
  let screenWidthElm = getSWElement();

  if (screenWidthElm) {
    let node = document.getElementById("screenWidth");
    if (node.parentNode) {
      node.parentNode.removeChild(node);
    }
    // console.log(`screenWidth should haven been removed`);
  }
  removeListeners();
}

function updateSW() {
  let screenWidthElm = getSWElement();

  if (screenWidthElm) {
    screenWidthElm.innerHTML = "" + window.innerWidth;
  }
  // console.log(`updateSW => ${window.innerWidth}`);
}

function removeListeners() {
  // console.log(`removeListeners`);

  // window.removeEventListener("load", init);
  window.removeEventListener("resize", updateSW);
  window.removeEventListener("unload", finish);
}

function addListeners() {
  // window.addEventListener("load", init);
  window.addEventListener("resize", updateSW);
  window.addEventListener("unload", finish);
}

if (!injected) {
  chrome.runtime.onMessage.addListener(function (
    request,
    sender,
    sendResponse
  ) {
    // console.log(
    //   sender.tab
    //     ? "from a content script:" + sender.tab.url
    //     : "from the extension"
    // );
    // console.log(`status: ${request.status}`);

    if (request.status === "OFF") {
      sendResponse({ farewell: "goodbye" });
      finish();
    }

    if (request.status === "ON") {
      sendResponse({ hello: "hallo" });
      init();
    }
  });
}