pimp_my_tube/extension/js/background.js

let browser = browser || chrome;

function sendMessageToCurrentTab(subject, value) {
    subject = subject || '';
    value = value || null;
    browser.tabs.query({active: true, currentWindow: true}, function(tabs){
       if (tabs !== []) {
          browser.tabs.sendMessage(tabs[0].id, {'subject' : subject, 'value' : value}, function(response) {});
          console.debug('send message to notification');
       }
    });
}

/**
* Retrieve data from local storage
* @param string key
*/
function getStorage(key) {

    return new Promise((resolve, reject) => {

        browser.storage.local.get(key, (items) => {
            resolve(items);
        });
    });
}

/**
* Set data into local storage
* @param string key
*/
function setStorage(key, value) {

    return new Promise((resolve, reject) => {

        getStorage(key)
            .then((items) => {

                let data = {};
                data[key] = value;

                browser.storage.local.set(data, () => {
                    resolve();
                });
            })
    });
}

browser.runtime.onMessage.addListener(function(message, sender, sendResponse){

    switch (message.subject) {
        case "updateBlacklist":
            console.debug("Keywords black list must be updated");
            let rawValue = message.value;
            let blacklist = rawValue.split(',').filter(n => n);
            blacklist = blacklist.map(function(keyword){
                return keyword.trim();
            });
            console.debug("Update list");
            setStorage('blacklist', blacklist).then(() => {
                sendMessageToCurrentTab('updateBlacklist', blacklist);
            });
            break;
        case "getBlacklist":
            getStorage('blacklist').then((items) => {
                sendResponse({'subject':'blacklistValues', 'value':items});
            });
        default:

    }

    return true;

});

browser.tabs.onUpdated.addListener(function (tabId, changeInfo, tab) {
   if (changeInfo.status == 'complete') {
       getStorage('blacklist').then((items) => {
          sendMessageToCurrentTab('tabsUpdated', items.blacklist);
       });
   }
});