bitwise JavaScript

bitwise.js

// how we calculate selectedDays
const days = _.range(0, 7).map((i) => {
  return {
    value: Math.pow(2, i)
  }
})

console.log(days)

const selectedDays = {
  "1": true, // sunday
  "2": true, // monday
  "4": true, // tuesday
  "8": true, // wednesday
  "16": true, // thursday
  "32": true, // friday
  "64": true // saturday
}

function calculateValue () {
  return Object.keys(selectedDays)
    // filter out falsy values
    .filter(el => selectedDays[el])
    // sum them up
    .reduce((acc, val) => acc + Number(val), 0)
}


function createSelectedDaysObjectFromCalculatedValue(value) {
  return _.range(0, 7).reduce((acc, val, i) => {
    const dayValue = Math.pow(2, i)
    acc[dayValue] = (value & dayValue) !== 0
    return acc
   }, {})
}

console.log(
  'The calculated value is: ',
  calculateValue()
)

console.log(
  'The source object is: ',
  createSelectedDaysObjectFromCalculatedValue(0)
)