输出显示NaN，但是我需要数组的和

function sumArray(arr) {
  return arr.reduce((acc, val) => {
    if (typeof val === 'number' && !isNaN(val)) {
      return acc + val;
    }
    return acc;
  }, 0);
}

const arr = [1, 2, '3', 4, null, undefined, NaN];
console.log(sumArray(arr)); // 输出: 7

function sumArray(arr) {
  const filteredArr = arr.filter(val => typeof val === 'number' && !isNaN(val));
  return filteredArr.reduce((acc, val) => acc + val, 0);
}

const arr = [1, 2, '3', 4, null, undefined, NaN];
console.log(sumArray(arr)); // 输出: 7