binary-gap-solution.js

function solution(N) {
	
  const nope = 0;
  
  if(!N) return nope;
  
  let bin = (N >>> 0).toString(2);

  let binLength = bin.length;
  
  if (!( bin.includes("0") )) return nope;
  
  bin = bin.split('1');

  if(!bin[binLength - 1]) bin[binLength - 1] = 1;
  
  bin = bin.filter(a => !!a);
  	
  binLength = bin.length; let maxIndex = binLength - 1;
  
  if (!!binLength) {
        let longest = 0, size;
        bin.map((a, i, arr) => {
			if(i !== maxIndex ) {
            	size = arr[i].split('').length;
            	if (size > longest) longest = size;
            }
        });
        return longest;
    }
  
};

// test it
let dec2bin = (dec) => (dec >>> 0).toString(2);
let logIt = (num) => console.log(num + " >>> " + dec2bin(num) + " - longest gap: " + solution(num));

logIt(9); // should log 2
logIt(15); // should log 0
logIt(1041); // should log 5
logIt(529); // should log 4