code every day with me

--DAY 13--

Hi, I am going to make #100DaysOfCode Challenge. Everyday I will try solve 1 problem from leetcode or hackerrank. Hope you can go with me until end.
Now let's solve problem today:

• Problem: Add binary
• Detail: here
• Idea: check sum of each pair binary number from tail.
  • ex: 1010, 1011
  • initiate empty string s, one left over = 0;
  • 1 + 0 + (oneleftover=0) = 1 -> s=1, oneleftover = 0
  • 1 + 1 + (oneleftover=0) = 0 -> s=10, set oneleftover = 1
  • 0 + 0 + (oneleftover=1) = 1 -> s=101, set oneleftover = 0
  • 1 + 1 + (oneleftover=0) = 0 -> s=1010, set oneleftover = 1
  • oneleftover = 1 -> s=10101
  • reverse string s : 10101
• My solution (javascript):

var addBinary = function(a, b) {
   let binary='',i=a.length-1,j=b.length-1,s=0;
    while(i>=0||j>=0||s){
       let digit = (+a[i]||0)+(+b[j]||0)+s;
       s=Math.floor(digit/2);
       binary+=(digit%2);
       i--;j--;
    }
    return binary.split('').reverse().join(''); 
};

-->If you have better solution or any question, please comment below. I will appreciate.