Can't get Firefox extension logs to show up

Solution 1:

Firefox console has been divided into different areas. The result of console.log() can be viewed in the relative area.

• Multiprocess Browser Console Ctrl+Shift+J
  Mostly logs by Firefox itself
• Web Developer Tools Ctrl+Shift+I or F12
  Logs by Tab/Webpage and Content scripts of addons
• Extension Toolbox about:debugging#/runtime/this-firefox ➜ XYZaddon ➜ Inspect
  Logs by background scripts of XYZaddon

Update

Based on comments, here is a tested simplified code that you can work on. The log shows on Extension Toolbox.

async function showCookiesForTab() {
  // get the first tab object in the array
  const tabs = await browser.tabs.query({currentWindow: true, active: true});

  // get all cookies in the domain
  const cookies = await browser.cookies.getAll({url: tabs[0].url});
  console.log(cookies);
  // Array(6) [ {…}, {…}, {…}, {…}, {…}, {…} ]
}

showCookiesForTab();