convert hex to rgd color

Hex to Rgb

 function stringToNumber(s) {
     
    let abc = [ '0','1','2','3','4','5','6','7','8','9','A' ,' B' , 'C' , 'D' , 'E' ,'F'];
    //let mark  = ['-','!','_','?','=',')','(','/','*','{','@',',','`','#','$','%','^','&','*','+','?','/','<','>']
    if (typeof s !== 'string' || !abc.includes(s.toUpperCase())) {
      return 'wrong'
    }

    //
    return   abc.indexOf(s.toUpperCase());

  // if(typeof s == 'string'){
  //   if(!abc.includes(s.toUpperCase()) || mark.includes(s) ){
        
  //     //  return '';
  //      return s*=s;
       
  //   }
  //    return   abc.indexOf(s.toUpperCase());

  // }else{
  //   return 'wrong'
  // }
  
}

//  return abc
// console.log(stringToNumber('-'));

function hextToDec(n1, n2) {
  return   n1 * 16 + n2;  
}

function convertToRGB(rr, gg, bb) {
    return `rgb(${rr},${gg},${bb})`;
}

// convertFromHex('#63C6FF');
function convertFromHex(hexColor){
  
    let r1, r2, g1, g2, b1, b2;// r1=r2 => r3 && g1= g2 => g3 && b1 = b2 => b3
    if (hexColor.length <= 5){
      r1 = stringToNumber(hexColor[1]);
      r2 = stringToNumber(hexColor[1]);
      let rr = hextToDec(r1,r2)
  
      g1 = stringToNumber(hexColor[2])
      g2 = stringToNumber(hexColor[2])
      let gg = hextToDec(g1,g2)
  
      b1 = stringToNumber(hexColor[3])
      b2 = stringToNumber(hexColor[3])
      let bb = hextToDec(b1,b2)
         
    if( isNaN(rr) || isNaN(gg) ||  isNaN(bb)){
      return 'input error you should just input number from 0 to 9 and A B C D E F and six digits as String';
     }
 // console.log(rr);
    return   convertToRGB(rr,gg,bb);
    } 
    r1 = stringToNumber(hexColor[1]);
    r2 = stringToNumber(hexColor[2]);
    let rr = hextToDec(r1,r2)

    g1 = stringToNumber(hexColor[3])
    g2 = stringToNumber(hexColor[4])
    let gg = hextToDec(g1,g2)

    b1 = stringToNumber(hexColor[5])
    b2 = stringToNumber(hexColor[6])
    let bb = hextToDec(b1,b2)
    
    if( isNaN(rr) || isNaN(gg) ||  isNaN(bb)){
     return 'input error you should just input number from 0 to 9 and A B C D E F and six digits as String';
    }
// console.log(rr);
   return   convertToRGB(rr,gg,bb);
 
};


console.log(convertFromHex(`#`));
// console.log(convertFromHex(`#11aaff`));