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 }