javascript - 循环不根据查询输出 true 或 false

Question

请看一下并告诉我为什么循环的输出不正确？

基本上，我循环遍历用户的friendId数组和用户搜索结果，看看它们是否匹配，根据匹配它应该返回true或false。

这是我的循环代码:

User.findById(req.signedCookies.userid, function(err, signedInUser) {
    //console.log(JSON.stringify(signedInUser.friendRequest));
    for (var x = 0; x < users.length; x++) {
        users[x].isFriend = false;
        //console.log(users[x].lastName);
        for (var i = 0; i < signedInUser.friendRequest.length; i++) {
            //  console.log(users[x]._id + ' - ' + signedInUser.friendRequest[i].friendId);
            //console.log(users[x].isFriend);
            if (users[x]._id === signedInUser.friendRequest[i].friendId) {
                users[x].isFriend = true;
                console.log('test');
                break;
            }
        }
    }
    res.render('searchResults', {
        title: 'Weblio',
        userAdded: users
    });
});

console.log 的输出:

 [{"friendId":"51ee2017c2023cc816000002","read":0,"date_requested":"2013-07-23T06
:29:39.021Z"},{"friendId":"51ee203cc2023cc816000003","read":0,"date_requested":"
2013-07-23T06:42:37.872Z"}]
Jones
51ee2017c2023cc816000002 - 51ee2017c2023cc816000002
false
51ee2017c2023cc816000002 - 51ee203cc2023cc816000003
false
Macks
51ee203cc2023cc816000003 - 51ee2017c2023cc816000002
false
51ee203cc2023cc816000003 - 51ee203cc2023cc816000003
false

登录用户是 John Smith，他搜索了 Jake

用户:约翰·史密斯 id 以 01 结尾 jack ·琼斯 02 完结 jack ·麦克斯以 03 结尾

实际上 Jake Macks 位于friendId 中

console.log('test');

没有被输出，所以我假设它甚至没有进入嵌套循环的if语句

以下是我在您移动的控制台日志之前调用的这些控制台日志的输入:

console.log(users);
console.log(signedInUser);
console.log(users[x].isFriend);

结果是:

[ { firstName: 'Jake',
    lastName: 'Jones',
    email: 'test2@gmail.com',
    password: '$2a$10$3ndDWiqOsyN.WN19fKJqq.xiC0B9da7QKTL74995zCT8vHrClo2uW',
    phone: 98439843943,
    birthday: Mon Jun 04 2012 20:00:00 GMT-0400 (Eastern Daylight Time),
    _id: 51ee2017c2023cc816000002,
    __v: 0,
    friend: [],
    friendRequest: [] },
  { firstName: 'Jake',
    lastName: 'Macks',
    email: 'test3@gmail.com',
    password: '$2a$10$XTsGrWmmOH/3O3eNwrNK2u.XOwl5cPPGyKrzgU0RMROcGTtU1LkDK',
    phone: 49372432922,
    birthday: Mon Jun 04 2012 20:00:00 GMT-0400 (Eastern Daylight Time),
    _id: 51ee203cc2023cc816000003,
    __v: 0,
    friend: [],
    friendRequest: [] } ]
{ __v: 0,
  _id: 51ee1ddbc2023cc816000001,
  birthday: Mon Aug 06 2012 20:00:00 GMT-0400 (Eastern Daylight Time),
  email: 'test1@gmail.com',
  firstName: 'John',
  lastName: 'Smith',
  password: '$2a$10$w6jTLvW.gUW5tY59/2/vIu8XPVsOe/NTr3e.Qc0WvVKIG8/MwSDW.',
  phone: 1122334422,
  friend: [],
  friendRequest:
   [ { date_requested: Tue Jul 23 2013 02:29:39 GMT-0400 (Eastern Daylight Time)
,
       read: 0,
       friendId: 51ee2017c2023cc816000002 },
     { date_requested: Tue Jul 23 2013 02:42:37 GMT-0400 (Eastern Daylight Time)
,
       read: 0,
       friendId: 51ee203cc2023cc816000003 } ] }
false
[ { firstName: 'Jake',
    lastName: 'Jones',
    email: 'test2@gmail.com',
    password: '$2a$10$3ndDWiqOsyN.WN19fKJqq.xiC0B9da7QKTL74995zCT8vHrClo2uW',
    phone: 98439843943,
    birthday: Mon Jun 04 2012 20:00:00 GMT-0400 (Eastern Daylight Time),
    _id: 51ee2017c2023cc816000002,
    __v: 0,
    friend: [],
    friendRequest: [] },
  { firstName: 'Jake',
    lastName: 'Macks',
    email: 'test3@gmail.com',
    password: '$2a$10$XTsGrWmmOH/3O3eNwrNK2u.XOwl5cPPGyKrzgU0RMROcGTtU1LkDK',
    phone: 49372432922,
    birthday: Mon Jun 04 2012 20:00:00 GMT-0400 (Eastern Daylight Time),
    _id: 51ee203cc2023cc816000003,
    __v: 0,
    friend: [],
    friendRequest: [] } ]
{ __v: 0,
  _id: 51ee1ddbc2023cc816000001,
  birthday: Mon Aug 06 2012 20:00:00 GMT-0400 (Eastern Daylight Time),
  email: 'test1@gmail.com',
  firstName: 'John',
  lastName: 'Smith',
  password: '$2a$10$w6jTLvW.gUW5tY59/2/vIu8XPVsOe/NTr3e.Qc0WvVKIG8/MwSDW.',
  phone: 1122334422,
  friend: [],
  friendRequest:
   [ { date_requested: Tue Jul 23 2013 02:29:39 GMT-0400 (Eastern Daylight Time)
,
       read: 0,
       friendId: 51ee2017c2023cc816000002 },
     { date_requested: Tue Jul 23 2013 02:42:37 GMT-0400 (Eastern Daylight Time)
,
       read: 0,
       friendId: 51ee203cc2023cc816000003 } ] }
false

Answer 1

您遇到的一个问题是您尝试记录 isFriend 结果的位置。当前，在您进入搜索循环时将 isFriend 设置为 false 后，就会记录该信息。

该语句需要移动到内部 for 循环之后。

如果没有所有输入，就很难猜测问题出在哪里。

使用以下内容作为输入(您能提供 JSON 格式的实际输入吗？):

var users = [
    {
        lastName: 'Smith',
        '_id': "51ee2017c2023cc816000001"
    },
    {
        lastName: 'Jones',
        '_id': "51ee2017c2023cc816000002"
    },
    {
        lastName: 'Macks',
        '_id': "51ee2017c2023cc816000003"
    }
];

var signedInUser = {
    friendRequest: [{
        "friendId": "51ee2017c2023cc816000002",
        "read": 0,
        "date_requested": "2013-07-23T06:29:39.021Z"
    }, {
        "friendId": "51ee203cc2023cc816000003",
        "read": 0,
        "date_requested": "2013-07-23T06:42:37.872Z"
    }]
};

function test(err, signedInUser) {
    console.log("\nsignedInUser.friendRequest\n" + JSON.stringify(signedInUser.friendRequest, null, 2));
    for (var x = 0; x < users.length; x++) {
        users[x].isFriend = false;
        console.log("\n" + users[x].lastName);
        for (var i = 0; i < signedInUser.friendRequest.length; i++) {
            console.log(users[x]._id + ' - ' + signedInUser.friendRequest[i].friendId);
            if (users[x]._id === signedInUser.friendRequest[i].friendId) {
                users[x].isFriend = true;
                console.log('test');
                break;
            }
        }
        console.log(users[x].isFriend);
    }

    console.log("\nFinal users:\n" + JSON.stringify(users, null, 2));
}

test(null, signedInUser);

我看到以下结果:

signedInUser.friendRequest
[
  {
    "friendId": "51ee2017c2023cc816000002",
    "read": 0,
    "date_requested": "2013-07-23T06:29:39.021Z"
  },
  {
    "friendId": "51ee203cc2023cc816000003",
    "read": 0,
    "date_requested": "2013-07-23T06:42:37.872Z"
  }
]

Smith
51ee2017c2023cc816000001 - 51ee2017c2023cc816000002
51ee2017c2023cc816000001 - 51ee203cc2023cc816000003
false

Jones
51ee2017c2023cc816000002 - 51ee2017c2023cc816000002
test
true

Macks
51ee2017c2023cc816000003 - 51ee2017c2023cc816000002
51ee2017c2023cc816000003 - 51ee203cc2023cc816000003
false

Final users:
[
  {
    "lastName": "Smith",
    "_id": "51ee2017c2023cc816000001",
    "isFriend": false
  },
  {
    "lastName": "Jones",
    "_id": "51ee2017c2023cc816000002",
    "isFriend": true
  },
  {
    "lastName": "Macks",
    "_id": "51ee2017c2023cc816000003",
    "isFriend": false
  }
]

除了日志语句位于错误的位置(我认为我没有更改代码的语义)之外，使用这组输入，逻辑可以正常工作。您所期望的输入可能不是您收到的。

事实证明，OP正在使用nodejs的mongoose native 驱动程序，经过研究，在这里找到了问题比较部分的答案:Comparing mongoose _id and strings