background.js

chrome.browserAction.setBadgeText({ text: "OFF" });
chrome.browserAction.setBadgeBackgroundColor({ color: "#4688F1" });
let reloads_holder = {};

const ON = 'ON';
const OFF = 'OFF';

// Main auto-reload function
chrome.storage.onChanged.addListener((whatChanged, area) => {
    if(area === "local") {
        const currentKey = Object.keys(whatChanged)[0];
        const currentVal = whatChanged[currentKey].newValue;

        if (typeof currentVal.active === 'boolean') {
            if (currentVal.active) {
                // Start reloading current tab
                const reloadInterval = currentVal.unit === 'min' ? currentVal.input * 60 * 1000 : currentVal.input * 1000;

                reloads_holder[currentKey] = setInterval(() => {
                    chrome.tabs.reload(parseInt(currentKey));
                }, reloadInterval);
            } else {
                // Stop reloading
                clearInterval(reloads_holder[currentKey]);
            }
        }
    }
});

// Update badge text
chrome.tabs.onActivated.addListener(()=>{
    chrome.tabs.query({ currentWindow: true, active: true }, function (tabs) {
        let tab = tabs[0];

        chrome.storage.local.get(tab.id.toString(), (items) => {
            if (items[tab.id] && items[tab.id].active) {
                chrome.browserAction.setBadgeText({ text: ON });
            } else {
                chrome.browserAction.setBadgeText({ text: OFF });
            }
        });
      });
});

// Catch tab removed and remove the related reloader.
chrome.tabs.onRemoved.addListener(function (tabId, removeInfo) {
    clearInterval(reloads_holder[tabId]);
});