Decode Base64 to Hexadecimal string with javascript

Question

Needing to convert a Base64 string to Hexadecimal with javascript.

Example:

var base64Value = \"oAAABTUAAg==\"

Need conversion m

Answer 1

Assuming you want the hexadecimal representation as a string, the window.atob function (available in most modern browsers) is your first step - it will convert your base64 string to an ASCII string, where each character represents one byte.

At this point you split the string, grab the character code of each character, then convert that to a left-padded base-16 string.

function base64ToBase16(base64) {
  return window.atob(base64)
      .split('')
      .map(function (aChar) {
        return ('0' + aChar.charCodeAt(0).toString(16)).slice(-2);
      })
     .join('')
     .toUpperCase(); // Per your example output
}

console.log(base64ToBase16("oAAABTUAAg==")); // "A0000005350002"

(Or try it on JSBin)