background.js

chrome.alarms.create("Timero Extension",{
    periodInMinutes: 1/60
})

chrome.alarms.onAlarm.addListener((alarm) => {
    if(alarm.name = "Time Extension") {
        chrome.storage.local.get(["timer", "isRunning", "timeOption"], (result) => {
            if(result.isRunning) {
                let timer = result.timer + 1
                let isRunning = true
                if(timer === 60 * result.timeOption) {
                    this.registration.showNotification("Time Extension", {
                        body: `${result.timeOption} minutes has passed !`,
                        icon: "clock.png"
                    })
                    timer = 0
                    isRunning=false
                }
                chrome.storage.local.set({timer, isRunning})
            }
        })
    }
})

chrome.storage.local.get(["timer", "isRunning", "timeOption"], (result) => {
    chrome.storage.local.set({
        timer: "timer" in result ? result.timer : 0,
        timeOption: "timeOption" in result ? result.timeOption : 25,
        isRunning: "isRunning" in result ? result.isRunning : false
    })
})