Binary Gap

TypeScript Binary Gap

function binaryGap(n: number): number {
  const trimmed = n.toString(2).replace(/^0+|0+$/g, "");
  const zeroes = trimmed.split("1");

  let gap = 0;
  for (const zero of zeroes) {
    gap = Math.max(gap, zero.length);
  }

  return gap;
}

This turns the number into binary, ignores zeroes outside the edges, and finds the longest run of zeroes between 1s.