function formatDate(data) { for (var i = 0; i < data.length; i++) { var dateString = data[i].petition_at; var date = new Date(dateString); var year = date.getFullYear(); var month = ("0" + (date.getMonth() + 1)).slice(-2); var day = ("0" + date.getDate()).slice(-2); data[i].petition_at = year + "-" + month + "-" + day + " " + hours dateString = data[i].created_at; date = new Date(dateString); year = date.getFullYear(); month = ("0" + (date.getMonth() + 1)).slice(-2); day = ("0" + date.getDate()).slice(-2); data[i].petition_at = year + "-" + month + "-" + day + " " + hours data[i].created_at = date.toLocaleString(); } return data; } return data = formatDate(data)哪里有错

这段代码有几处小错误：

1. 在第一行的 `function formatDate(data)` 后面缺少一个左括号 `(`。
2. 在第三个 `var` 声明中，变量 `hours` 没有被定义，应该是 `date.getHours()`。
3. 在第六行和第九行，将 `petition_at` 改成了 `created_at`，这是无意义的，应该将第九行的 `petition_at` 改成 `created_at`。

下面是修正后的代码：

function formatDate(data) {
  for (var i = 0; i < data.length; i++) {
    var dateString = data[i].petition_at;
    var date = new Date(dateString);
    var year = date.getFullYear();
    var month = ("0" + (date.getMonth() + 1)).slice(-2);
    var day = ("0" + date.getDate()).slice(-2);
    var hours = date.getHours();
    data[i].petition_at = year + "-" + month + "-" + day + " " + hours;

    dateString = data[i].created_at;
    date = new Date(dateString);
    year = date.getFullYear();
    month = ("0" + (date.getMonth() + 1)).slice(-2);
    day = ("0" + date.getDate()).slice(-2);
    data[i].created_at = year + "-" + month + "-" + day + " " + hours;
    data[i].petition_at = date.toLocaleString();
  }
  return data;
}
data = formatDate(data);