对特定属性具有相同值的元素进行计数，并将结果放入对象数组中

function countElementsWithSameValue(elements, property) {
  var countArray = [];

  elements.forEach(function(element) {
    var value = element[property];
    var existingObject = countArray.find(function(obj) {
      return obj[property] === value;
    });

    if (existingObject) {
      existingObject.count++;
    } else {
      var newObject = {};
      newObject[property] = value;
      newObject.count = 1;
      countArray.push(newObject);
    }
  });

  return countArray;
}

// 示例用法
var elements = [
  { name: 'A', category: 'X' },
  { name: 'B', category: 'Y' },
  { name: 'C', category: 'X' },
  { name: 'D', category: 'Z' },
  { name: 'E', category: 'X' },
  { name: 'F', category: 'Y' },
  { name: 'G', category: 'Z' },
  { name: 'H', category: 'X' }
];

var result = countElementsWithSameValue(elements, 'category');
console.log(result);

[
  { category: 'X', count: 4 },
  { category: 'Y', count: 2 },
  { category: 'Z', count: 2 }
]