javascript - 在nodejs中将现有对象查找到数组中

Question

您好，这是我的收藏，如果两个 userId 都存在于订阅者数组中，我只想将 userId 查看到订阅者数组中，而不是创建新集合返回相同的 channelId。如果两个 userId 都不存在于 subcriber 数组中，那么创建新文档我如何在数组中搜索 userids。这是我的收藏。

{
"_id" : ObjectId("58dd1013e973fc0004743443"),
"createdAt" : ISODate("2017-03-30T14:02:59.175Z"),
"updatedAt" : ISODate("2017-03-30T14:02:59.175Z"),
"timestamp" : "2017-03-30",
"channelId" : "CH-EU7D",
"createdById" : "58dcc3cd9a7a301308b62857",
"message" : "",
"subcriber" : [ 
    {
        "userId" : "58dcc3cd9a7a301308b62857",
        "channelId" : "CH-EU7D",
        "_id" : ObjectId("58dd1013e973fc0004743444"),
        "status" : "accepted"
    }, 
    {
        "userId" : "58dcc3ec9a7a301308b62859",
        "channelId" : "CH-EU7D",
        "_id" : ObjectId("58dd1013e973fc0004743445"),
        "status" : "pending"
    }
],
"__v" : 0

我已经试过了，但没有用。

Channel.find({ 'subcriber.userId': b.userId }, { $and: [{ 'subcriber.userId': b.friendId }] }

Answer 1

在 nodejs 中你可以使用 JavaScript Array.prototype.some()方法与您的 json 数组来测试是否有任何匹配的 useId，您需要编写如下内容:

function checkUserId(array, userId) {
  return array.some(function(element) {
    return userId === element.userId;
  });
}

这是一个演示片段:

function checkUserId(array, userId) {
  return array.some(function(element) {
    return userId === element.userId;
  });
}


var json = {
  "_id": "58dd1013e973fc0004743443",
  "createdAt": "2017-03-30T14:02:59.175Z",
  "updatedAt": "2017-03-30T14:02:59.175Z",
  "timestamp": "2017-03-30",
  "channelId": "CH-EU7D",
  "createdById": "58dcc3cd9a7a301308b62857",
  "message": "",
  "subcriber": [{
      "userId": "58dcc3cd9a7a301308b62857",
      "channelId": "CH-EU7D",
      "_id": "58dd1013e973fc0004743444",
      "status": "accepted"
    },
    {
      "userId": "58dcc3ec9a7a301308b62859",
      "channelId": "CH-EU7D",
      "_id": "58dd1013e973fc0004743445",
      "status": "pending"
    }
  ]
};

//Check an existing userId
console.log(checkUserId(json.subcriber, "58dcc3ec9a7a301308b62859"));

//Check a non existing userId
console.log(checkUserId(json.subcriber, "58dcc3ec9a7a3000000000859"));