Binary Gap Algorithm in javascript ES6

app.js

//A binary gap within a positive integer N is any maximal sequence of consecutive zeros that is surrounded by ones at both ends in the binary representation of N.
const toBinaryString = number => {
  return number.toString(2); // returns a string
};

function solution(N) {
  const nBinaryString = toBinaryString(N);
  let numberOfZeroes = 0;
  let max = 0;
  // loop through letters
  for (let i = 0; i < nBinaryString.length; i++) {
    if (nBinaryString.charAt(i) === '1') {
      if (numberOfZeroes > max) {
        max = numberOfZeroes;
      }
      numberOfZeroes = 0;
      continue;
    } else {
      numberOfZeroes++;
    }
  }
  return max;
}