Simple Counter Class using a ttl for counts

TtlCounter.js

class TtlCounter {
   constructor (ttl) {
      this._count = 0
      this._ttl = ttl
   }

   get value () {
      return this._count
   }

   count () {
      this._count++
      setTimeout(function () {
         this._count--
      }.bind(this), this._ttl)
   }
}