Observer Pattern pt2

fluxmodel.js

class FluxModel extends EventEmitter {
  constructor() {
    super() // initialize the EventEmitter
    this.time = new Date() // set the current time
    this.isNighttime = this.getNighttime() // check if it is nighttime
    setInterval(this.updateTime.bind(this), 60000) // update our model's state every minute
  }

  updateTime() {
    let previousIsNighttimeState = this.isNighttime // save the PREVIOUS STATE of our application
    this.time = new Date() // set the CURRENT STATE of our application
    this.isNighttime = this.getNighttime()
    // trigger event on a STATE change (going from day to night)
    if (previousIsNighttimeState && !this.isNighttime) { // from night to day
      this.dispatchEvent('daytime', this.time)
    } else if (!previousIsNighttimeState && this.isNighttime) { // from day to night
      this.dispatchEvent('nighttime', this.time)
    }
  }

  getNighttime() {
    return this.time.getHours() > 18 && this.time.getHours() < 6
  }
}