Predict the future with javascript

predict.js

var predictions = predict(913,new Date())
console.log(predictions)

function predict(count,date) {
  var timestamp = date.getTime()
  var y = date.getFullYear(), m = date.getMonth(), d = date.getDate()
  
  var beginningOfDay = new Date(y, m, d).getTime()
  var endOfDay = new Date(y, m, d+1).getTime()
  var pacePerDay = count / (timestamp - beginningOfDay)
  var restPerDay = pacePerDay * (endOfDay - timestamp)
  var dayTotal = Math.round(count + restPerDay)
 
  var beginningOfWeek = getStartOfWeek(new Date(y, m, d).getTime())
  var endOfWeek = getEndOfWeek(new Date(y, m, d).getTime())
  var pacePerWeek = count / (timestamp - beginningOfWeek)
  var restPerWeek = pacePerWeek * (endOfWeek - timestamp)
  var weekTotal = Math.round(count + restPerWeek)

  var beginningOfMonth = new Date(y, m, 1).getTime()
  var endOfMonth = new Date(y, m+1, 1).getTime()
  var pacePerMonth = count / (timestamp - beginningOfMonth)
  var restPerMonth = pacePerMonth * (endOfMonth - timestamp)
  var monthTotal = Math.round(count + restPerMonth)
  
  var beginningOfYear = new Date(y, 0).getTime()
  var endOfYear = new Date(y+1, 0).getTime()
  var pacePerYear = count / (timestamp - beginningOfYear)
  var restPerYear = pacePerYear * (endOfYear - timestamp)
  var yearTotal = Math.round(count + restPerYear)

  predictions = {
    "year" : yearTotal,
    "month" : monthTotal,
    "week" : weekTotal,
    "day" : dayTotal
  }
  return predictions
}

function getStartOfWeek(timestamp) {
  var date = new Date(timestamp)
  if (date.getDay()) {
    date.setHours(-Math.abs(date.getDay() - 1) * 24, 0, 0, 0)
  } else {
    date.setHours(-6 * 24, 0, 0, 0)
  }
  return date.getTime()
}

function getEndOfWeek(timestamp) {
  var startDate = getStartOfWeek(timestamp)
  var endDate = new Date(startDate)
  endDate.setHours(7 * 24, 0, 0, 0)
  return endDate.getTime()
}