longestPrefix.ts

function longestPrefix(strings: string[]) {
  const { 0: first, [strings.length - 1]: last } = [...strings].sort();
  let prefixLength = -1;
  for (let i = 0; i < Math.min(first.length, last.length); i++) {
    if (first[i] === last[i]) {
      prefixLength = i;
    } else {
      break;
    }
  }

  return first.slice(0, prefixLength + 1);
}