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循環不輸出真或假請看看並讓我知道爲什麼循環的輸出不正確？

基本上我循環瀏覽用戶的friendId數組，並通過用戶搜索結果查看它們是否匹配，具體取決於匹配，它應該返回true或false。

這裏是我的循環代碼：

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 
    }); 
}); 

的console.log輸出：

[{"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 

在用戶簽訂的是約翰·史密斯和他搜索傑克

用戶： John Smith id結束於01 傑克瓊斯結束於02 傑克麥克斯結束於03

個

凡其實傑克Macks在friendId

console.log('test'); 

沒有被outputed，所以我假設它甚至沒有進入嵌套循環

這裏的if語句是用於輸入這些控制檯日誌我叫權控制檯登錄之前你感動：

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

的結果是：

[ { 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

您遇到的一個問題是您嘗試記錄isFriend結果的位置。當您在進入搜索循環時將isFriend設置爲false後，它正在記錄。

該語句需要在inner for循環之後移動。

如果沒有所有的輸入，就很難猜測問題出在哪裏。

使用以下內容作爲輸入（您可以提供JSON格式的實際輸入內容嗎？）：

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); 

我看到以下結果：

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 
    } 
] 

除了日誌語句在錯誤的地點（我不認爲我改變了你的代碼的語義），這一套的輸入，邏輯起作用。您期望的輸入可能不是您正在接收的內容。

原來，OP用貓鼬本地驅動程序和的NodeJS，研究後找到了答案，這裏的問題比較部分：Comparing mongoose _id and strings

Answer 2

我建議比較值，而不是對象 - 使用==，不===，在此基礎上：

Why Array.indexOf doesn't find identical looking objects

Answer 3

這是一種野生的猜測，但我懷疑你正試圖在這裏返回值：

res.render('searchResults', {title: 'Weblio', userAdded: users }); 

如果是這樣，用戶添加會有下的用戶集合userAdded，不是真/假。

當您斷開循環並將該變量用作返回值時，您可能需要將布爾值設置爲true（例如，myVariable = true）。