WorkerTimers wrapper to count and save duration into localStorage
npm install --save persistent-duration
import * as duration from 'persistent-duration'
// Set an interval on worker, func will increment the duration every 1000ms
const intervalId = duration.start()
// Stop the interval.
// Keep in mind that duration still persists even though
// you have stopped the interval
duration.stop(intervalId)
// Get duration (returns a number)
duration.get()
// Remove duration from localStorage
duration.clear()