HexToDecimal.js

function hexToInt (hexNum) {
 const numArr = hexNum.split('') // converts number to array
 return numArr.map((item, index) => {
 switch (item) {
 case 'A': return 10
 case 'B': return 11
 case 'C': return 12
 case 'D': return 13
 case 'E': return 14
 case 'F': return 15
 default: return parseInt(item)
 }
 })
}

function hexToDecimal (hexNum) {
 const intItemsArr = hexToInt(hexNum)
 return intItemsArr.reduce((accumulator, current, index) => {
 return accumulator + (current * Math.pow(16, (intItemsArr.length - (1 + index))))
 }, 0)
}

export { hexToInt, hexToDecimal }