js 快速求多组数的并集

function unionArrays(...arrays) {
  const unionSet = new Set();
  arrays.forEach(array => {
    array.forEach(num => {
      unionSet.add(num);
    });
  });
  return Array.from(unionSet);
}

// 示例用法：
const array1 = [1, 2, 3];
const array2 = [2, 3, 4];
const array3 = [4, 5, 6];

const union = unionArrays(array1, array2, array3);
console.log(union); // 输出: [1, 2, 3, 4, 5, 6]