Having to deal with many file header format i.e. bmp, tiff, wav, mp3, etc... I developed a few basic routines to deal with them. I was wondering if there was a better way? Also they do not deal with signed nor float value.

  function Read2BytesToUWord   (ThisArray, Offset, UseLittleEndian){

    let ThisWord              = 0;

    if(UseLittleEndian){
      ThisWord               |= ThisArray[Offset + 1].charCodeAt() << 8;
      ThisWord               |= ThisArray[Offset + 0].charCodeAt();
    } else {
      ThisWord                = ThisArray[Offset + 0].charCodeAt();
      ThisWord               |= ThisArray[Offset + 1].charCodeAt() << 8;
    }
    return Number((ThisWord));
  }
  function Read4BytesToUDWord   (ThisArray, Offset, UseLittleEndian){

    let ThisDWord             = 0;

    if(UseLittleEndian){
      ThisDWord               = ThisArray[Offset + 3].charCodeAt() << 24;
      ThisDWord              |= ThisArray[Offset + 2].charCodeAt() << 16;
      ThisDWord              |= ThisArray[Offset + 1].charCodeAt() << 8;
      ThisDWord              |= ThisArray[Offset + 0].charCodeAt();
    } else {
      ThisDWord               = ThisArray[Offset + 3].charCodeAt();
      ThisDWord              |= ThisArray[Offset + 2].charCodeAt() << 8;
      ThisDWord              |= ThisArray[Offset + 1].charCodeAt() << 16;
      ThisDWord              |= ThisArray[Offset + 0].charCodeAt() << 24;
    }
    return Number((ThisDWord));
  }
  function ReadBytesToString    (ThisArray, Offset, ThisLen){
    let ThisStr  = "";
    for(let Indx = 0; Indx < ThisLen; Indx++){
      ThisStr   += (ThisArray[Offset + Indx]); 
    }
    return ThisStr;
  }