在javascript中检查数组中有多少元素作为键存在于对象中

function countKeys(arr, obj) {
  let count = 0;
  for (let i = 0; i < arr.length; i++) {
    if (obj.hasOwnProperty(arr[i])) {
      count++;
    }
  }
  return count;
}

const array = [1, 2, 3, 4];
const object = { 1: 'a', 2: 'b', 3: 'c' };
console.log(countKeys(array, object)); // Output: 3

function countKeys(arr, obj) {
  const filteredArray = arr.filter(key => obj.hasOwnProperty(key));
  return filteredArray.length;
}

const array = [1, 2, 3, 4];
const object = { 1: 'a', 2: 'b', 3: 'c' };
console.log(countKeys(array, object)); // Output: 3

function countKeys(arr, obj) {
  return arr.reduce((count, key) => {
    if (obj.hasOwnProperty(key)) {
      count++;
    }
    return count;
  }, 0);
}

const array = [1, 2, 3, 4];
const object = { 1: 'a', 2: 'b', 3: 'c' };
console.log(countKeys(array, object)); // Output: 3