创建一个函数，将数据数组动态转换为表的列标题

function convertToTableHeaders(dataArray) {
  var headers = [];

  if (dataArray.length === 0) {
    return headers;
  }

  var firstDataItem = dataArray[0];

  for (var key in firstDataItem) {
    headers.push(key);
  }

  return headers;
}

var data = [
  { name: 'John', age: 25, city: 'New York' },
  { name: 'Emily', age: 30, city: 'London' },
  { name: 'Mike', age: 35, city: 'Paris' }
];

var tableHeaders = convertToTableHeaders(data);
console.log(tableHeaders);
// 输出: ["name", "age", "city"]