从联合类型typescript生成字符串数组

function filterStrings(arr: (string | number)[]): string[] {
  const result: string[] = [];
  for (const item of arr) {
    if (typeof item === 'string') {
      result.push(item);
    }
  }
  return result;
}

const unionArr: (string | number)[] = ['apple', 123, 'banana', 456, 'orange'];
const stringArr: string[] = filterStrings(unionArr);
console.log(stringArr); // 输出：['apple', 'banana', 'orange']