如何循环MongoDB中的数组？

这是我的代码来循环用户的结果，然后我试图循环通过search从用户做出的朋友请求数组。 但是，我不断得到一个TypeError：无法读取属性'$ elemMatch未定义。 我正在使用mongoose和Node.Js和这个searchPost在路由文件夹。

exports.searchPost = function(req, res, err) { User.find({$or:[ {firstName: req.body.firstName}, {lastName: req.body.lastName}, {email: req.body.email}, {phone: req.body.phone}] }, function(err, users, userAdd) { if(err) { return res.render('searchError', {title: 'Weblio'}); } else { if(req.body.firstName=== '' && req.body.lastName==='' && req.body.email==='' && req.body.phone=== '') { return res.render('searchError', {title: 'Weblio'}); } else { for(x in users) { User.findById(req.signedCookies.userid, {friendRequest: x.id} if(x.id === true ) { console.log('addman1'); return userAdd = false; } else { console.log('addman2'); return userAdd = true; } }); } return res.render('searchResults', {title: 'Weblio', usersFound: users, userAdded: userAdd }); } } }); }; 

错误：

 TypeError: Cannot read property '$elemMatch' of undefined at Query._castFields (C:\Users\Lior\Desktop\nodep\test5\node_modules\mongoos e\lib\query.js:2203:22) at Query.findOne (C:\Users\Lior\Desktop\nodep\test5\node_modules\mongoose\li b\query.js:1775:25) at Function.findOne (C:\Users\Lior\Desktop\nodep\test5\node_modules\mongoose \lib\model.js:944:16) at Function.findById (C:\Users\Lior\Desktop\nodep\test5\node_modules\mongoos e\lib\model.js:882:15) at Promise.<anonymous> (C:\Users\Lior\Desktop\nodep\test5\routes\user.js:193 :12) at Promise.<anonymous> (C:\Users\Lior\Desktop\nodep\test5\node_modules\mongo ose\node_modules\mpromise\lib\promise.js:162:8) at Promise.EventEmitter.emit (events.js:95:17) at Promise.emit (C:\Users\Lior\Desktop\nodep\test5\node_modules\mongoose\nod e_modules\mpromise\lib\promise.js:79:38) at Promise.fulfill (C:\Users\Lior\Desktop\nodep\test5\node_modules\mongoose\ node_modules\mpromise\lib\promise.js:92:20) at C:\Users\Lior\Desktop\nodep\test5\node_modules\mongoose\lib\query.js:1725 :26 [ERROR] 17:23:30 TypeError 

Answer 1

我想你可能正在尝试做这样的事情

 var totalDocsToProcess = users.length; for(var i = 0; i < users.length; i++) { User.findById(req.signedCookies.userid, function(err, x) { totalDocsToProcess = totalDocsToProcess - 1; if(x.id === true ) { console.log('addman1'); return userAdd = false; } else { console.log('addman2'); return userAdd = true; } if(totalDocsToProcess == 0) { return res.render('searchResults', {title: 'Weblio', usersFound: users, userAdded: userAdd }); } }) } 

Answer 2

for(x in users) x是数组的关键字而不是值，您应该尝试：

 for(var i = 0; i < users.length; ++i) { var x = users[i]; etc etc