BinaryToHex.js

const pad = (num, padlen) => {
 const pad = new Array(1 + padlen).join(0)
 return (pad + num).slice(-pad.length)
}

const hexLookup = (bin) => {
 let binary = bin
 if (binary.length < 4) {
 binary = pad(binary, 4)
 }
 switch (binary) {
 case '0000': return '0'
 case '0001': return '1'
 case '0010': return '2'
 case '0011': return '3'
 case '0100': return '4'
 case '0101': return '5'
 case '0110': return '6'
 case '0111': return '7'
 case '1000': return '8'
 case '1001': return '9'
 case '1010': return 'A'
 case '1011': return 'B'
 case '1100': return 'C'
 case '1101': return 'D'
 case '1110': return 'E'
 case '1111': return 'F'
 }
}
const binaryToHex = (binaryString) => {
 /*
 Function for convertung Binary to Hex

 1. The conversion will start from Least Significant Digit (LSB) to the Most Significant Bit (MSB).
 2. We divide the bits into sections of 4-bits starting from LSB to MSB.
 3. If the MSB get less than 4 bits, then we pad 0s to the front of it.

 For Example:
 Binary String = '1001101'

 1. Divide it to 2 parts => ['100', '1101']
 2. Pad 0s the MSB so it'll be => ['0100', '1101']
 3. Use the lookup table and merge them, therefore the result is 4D.

 */

 let result = ''
 binaryString = binaryString.split('')
 for (let i = binaryString.length - 1; i >= 0; i = i - 4) {
 if (i >= 3) {
 result += hexLookup(binaryString.slice(i - 3, i + 1).join(''))
 } else {
 result += hexLookup(binaryString.slice(0, i + 1).join(''))
 }
 }
 return result.split('').reverse().join('')
}

export default binaryToHex