Maximum Length of a Concatenated String with Unique Characters

export function maxLength(arr: string[]): number {
  const unique: Set<string>[] = [];
  for (const word of arr) {
    const wordSet = new Set(word);
    if (wordSet.size === word.length) {
      unique.push(wordSet);
    }
  }
 
  const concat: Set<string>[] = [new Set()];
  for (const u of unique) {
    for (const c of concat) {
      if (intersect(u, c).size === 0) {
        concat.push(union(u, c));
      }
    }
  }
 
  const answer = concat.reduce((prev, curr) => Math.max(prev, curr.size), 0);
  return answer;
}
 
function intersect<T>(set1: Set<T>, set2: Set<T>) {
  return new Set([...set1].filter((x) => set2.has(x)));
}
 
function union<T>(set1: Set<T>, set2: Set<T>) {
  return new Set([...set1, ...set2]);
}