javascript - 我如何从 mongodb 解析这个 json 以便与 Meteor Helper 一起使用

Question

我在一个集合中有这个json数据，我需要获取first_yr、second_yr_sem_1、second_yr_sem_2 ....的所有字段/值。

  {
    "first_yr": [
                  {
                   "subject_name": "Subject1",
                   "subject_val": "subject1"
                 },
                 {
                   "subject_name": "Subject2",
                   "subject_val": "subject2"
                 },
                 {
                   "subject_name": "Subject3",
                   "subject_val": "subject3"
                 },
                 {
                   "subject_name": "Subject4",
                   "subject_val": "subject4"
                 },
                 {
                   "subject_name": "Subject5",
                   "subject_val": "subject5"
                 },
                 {
                   "subject_name": "Subject6",
                   "subject_val": "subject6"
                 }
              ]

  },
  {
    "second_yr_sem_1":
              [
                {
                 "subject_name": "Subject1",
                 "subject_val": "subject1"
               },
               {
                 "subject_name": "Subject2",
                 "subject_val": "subject2"
               },
               {
                 "subject_name": "Subject3",
                 "subject_val": "subject3"
               },
               {
                 "subject_name": "Subject4",
                 "subject_val": "subject4"
               },
               {
                 "subject_name": "Subject5",
                 "subject_val": "subject5"
               },
               {
                 "subject_name": "Subject6",
                 "subject_val": "subject6"
               }
              ]

  },
  {
    "second_yr_sem_2":
                [
                  {
                   "subject_name": "Subject1",
                   "subject_val": "subject1"
                 },
                 {
                   "subject_name": "Subject2",
                   "subject_val": "subject2"
                 },
                 {
                   "subject_name": "Subject3",
                   "subject_val": "subject3"
                 },
                 {
                   "subject_name": "Subject4",
                   "subject_val": "subject4"
                 },
                 {
                   "subject_name": "Subject5",
                   "subject_val": "subject5"
                 },
                 {
                   "subject_name": "Subject6",
                   "subject_val": "subject6"
                 }
              ]

  }

与 meteor 助手一起使用

<select name="subject">
         {{#each subjects}}
         <option value="{{subject_val}}">{{subject_name}}</option>
         {{/each}}
</select>

那么，我应该返回给帮助者(主题)的 mongodb 查询应该是什么？!我被困住了，任何事情都可以帮助我!谢谢!!

Answer 1

抱歉，我不明白你的意思。因此，我假设您将 Json 直接保存在集合中，并且我认为您可以使用 cursor.forEach 将每个字符串解析为 template.helpers:

Template["myTemplate"].helpers({
  var subjects = [];
  var myDataCursor = MyCollection.find();
  myDataCursor.forEach(function(eachSubject) {
    subjects.push(JSON.parse(eachSubject));  // parse str to object, and save it in an array.
  });
  return subjects;
})

您可以找到更多详细信息here

我希望这能完美解决您的问题:-)