background.js

'use strict'

chrome.runtime.onInstalled.addListener(() => {
  chrome.declarativeContent.onPageChanged.removeRules(undefined, () => {
    chrome.declarativeContent.onPageChanged.addRules([
      {
        conditions: [
          new chrome.declarativeContent.PageStateMatcher({
            // Aqui podem ser adicionadas condições para que a extenssão seja ativada
          })
        ],
        actions: [new chrome.declarativeContent.ShowPageAction()]
      }
    ])
  })

  chrome.runtime.onConnect.addListener(port => {
    port.onMessage.addListener(msg => {
      port.postMessage({ counter: msg.counter + 1 })
    })
  })

  chrome.extension.onRequest.addListener((request, sender, sendResponse) => {
    zsendResponse({ counter: request.counter + 1 })
  })

  chrome.runtime.onMessage.addListener((response, sender, sendResponse) => {
    alert(response)
  })
})