Array.join('') is not working as it should inside of my recursive function

Question

I am attempting to use a recursive approach in order to write a function that will take in a binary string, break it apart into 8 bit sections, and return the string translated to ASCII. As far as I can tell from the running debugger, my function should be working. The only problem I'm running into is that when I call join('') on my 'currentArray' variable, it is not in fact joining the array. Any input would be helpful into what I am doing wrong here.

function binaryToString(binaryBlob, finalString = []) {
      if (binaryBlob.length === 0) return finalString.join('');
    
      let currentArray = [];
      let binaryArray = binaryBlob.split('');
    
      currentBit = binaryArray.splice(0, 8);
    
      currentArray.push(currentBit);
        
      let joinedString = currentArray.join('');
      let base10String = Number(joinedString);
      let ASCII = String.fromCharCode(base10String);
      finalString.push(ASCII);
    
      return binaryToString(binaryArray.join(''), currentArray, finalString);
    };

Expected outputs:

console.log(binaryToString('010000010100001001000011')); // should return 'ABC'
console.log(binaryToString('001101100011011100111000')); // should return '678'

Answer 1

A couple things:

• Having variables properly named after their type helps for clarity. Name an array finalArr instead of finalString, etc.
• currentArray doesn't seem to be necessary. Use slice directly on the string to get the first 8 characters for the byte, and slice again to provide the remaining characters to the next call.

Here is a slightly refactored version that makes it clearer:

function binaryToString(binaryStr, asciiArr = []) {
  if (binaryStr.length === 0) {
    return asciiArr.join('');
  }

  const byteStr = binaryStr.slice(0, 8);
  const remaining = binaryStr.slice(8);
  
  const byte = parseInt(byteStr, 2); // `2` indicates base of input string
  const ascii = String.fromCharCode(byte);
  asciiArr.push(ascii);

  return binaryToString(remaining, asciiArr);
};

console.log(binaryToString('010000010100001001000011')); // 'ABC'
console.log(binaryToString('001101100011011100111000')); // '678'