background.js

var sbId, sbPrevUrl;
// Create the window and save the tab id
browser.runtime.onMessage.addListener(function (request, sender, sendResponse) {
  if (request.type === 'share-backid') {
    browser.windows.create(request.data).then(function (tab) {
      sbId = tab.id;
      sbPrevUrl = request.data.url;
      return tab.id;
    });
  } else if (request.type === 'share-backid-container') {
    browser.tabs.create(request.data).then(function (tab) {
      sbId = tab.id;
      sbPrevUrl = request.data.url;
      return tab.id;
    });
  }
});

// Autoclose the window when the url change
browser.tabs.onUpdated.addListener(function (tabId, changeInfo, tab) {
  if (sbId === tab.windowId) {
    console.log(sbPrevUrl)
    const cssInjectionsFor = [
      'https://www.reddit.com/',
      'shaarli'
    ];

    if (sbPrevUrl !== undefined) {
      // True if any of the listed links show up
      const shallInjectCss = cssInjectionsFor.some(function (urlPart) {
        return sbPrevUrl.includes(urlPart);
      });

      if (shallInjectCss) {
        browser.tabs.insertCSS(tabId, {
          code: 'body { overflow: auto !important; }'
        });
      }
    }

    urlChangeStrategy(tabId, sbPrevUrl);
  }
});

function urlChangeStrategy(tabId, sbPrevUrl) {
  const closeWhen = ['latest_status_id='];

  const closeCarefullyWhen = [
    'reddit\.com\/user\/.+\/comments\/.+\/',
    'reddit\.com\/r\/.+\/comments\/.+\/',
    'twitter\.com\/home'
  ];

  const closeCarefullyOnlyIf = [
    'https://www.facebook.com/'
  ];

  browser.tabs.get(tabId, function (tabinfo) {
    const modalUrl = tabinfo.url;
    console.log(modalUrl)

    if (sbPrevUrl !== modalUrl && modalUrl !== 'about:blank') {
      // True if any of above parts are part of the modal URL
      var shallClose = closeWhen.some(function (urlPart) {
        return modalUrl.includes(urlPart);
      });

      if (!shallClose) {
        shallClose = closeCarefullyWhen.some(function (regex) {
          var testUrl = RegExp(regex, 'g');

          return testUrl.test(modalUrl);
        });

        if (!shallClose) {
          shallClose = closeCarefullyOnlyIf.some(function (url) {
            return url == modalUrl;
          });
        }
      }

      if (shallClose) {
        browser.tabs.remove(tabId);
      }
    }
  });
}

// call function which get the address bar color (toolbar_field)
setPageActionIcon();

async function setPageActionIcon() {
  var themeInfo = await browser.theme.getCurrent();
  let color = 'light';
  var rgb_list = ['rgb(71, 71, 73)', 'rgb(50, 50, 52)']; // list of RGB where icon_theme should be light
  if (themeInfo.colors && themeInfo.colors.toolbar_field) {
    if (!rgb_list.includes(themeInfo.colors.toolbar_field.toString())) {
      color = 'dark';
    }
  }
  setPageAction(color);
}

function setPageAction(color) {
  var ext_icon = 'icon-' + color + '.svg';
  browser.tabs.onUpdated.addListener(function (tabId, changeInfo, tab) {
    var getting = browser.storage.local.get('pageaction');
    getting.then(
      function (result) {
        var pageaction = result.pageaction;
        if (!pageaction) {
          if (
            tab.url.indexOf('about:') !== 0 &&
            tab.url.indexOf('moz-extension:') !== 0
          ) {
            browser.pageAction.setIcon({
              tabId: tab.id,
              path: ext_icon
            });

            browser.pageAction.setTitle({
              tabId: tab.id,
              title: 'Share'
            });

            browser.pageAction.show(tab.id);
            browser.pageAction.setPopup({
              tabId,
              popup: '/modal/modal.html'
            });
          }
        }
      },
      function (error) {
        console.log(`Error: ${error}`);
      }
    );
  });
}