通过_id的MongoDB Node.js deleteOne不能在ObjectId上运行(MongoDB Node.js deleteOne via _id doesn't work on ObjectId)

 我正在尝试在mongo DB包装器上编写测试（规范）并偶然发现这个奇怪的问题。 
 
 我的代码构建在mongodb的瘦包装之上，将_id作为字符串暴露给世界，但在与mongo交谈时使用（转换）它们到ObjectId。 
 
 我有一个助手创建灯具： 
 
var _ = require('lodash'),
    Promise = require('bluebird'),
    MongoDb = require('mongodb');

var fixtureData = [
    {
        'uuid': '1',
        'owner': 'A',
        'data': 'someData1'
    },
    {
        'uuid': '2',
        'owner': 'A',
        'data': 'someData2'
    },
    {
        'uuid': '3',
        'owner': 'B',
        'data': 'someData3'
    },
    {
        'uuid': '4',
        'owner': 'A',
        'data': 'someData4'
    },
    {
        'uuid': '5',
        'owner': 'A',
        'data': 'someData5'
    },
    {
        'uuid': '6',
        'owner': 'B',
        'data': 'someData6'
    }
]

module.exports.loadFixtures  = function (url, collectionName) {
    var MongoClient = MongoDb.MongoClient;

    return MongoClient.connect(url, {
        promiseLibrary: Promise
    }).then(function (db) {
        return db.dropCollection(collectionName)
            .catch(function (err) {
                if (err.message === 'ns not found') {
                    return 'does not exist';
                }
                throw err;
            })
            .then(function () {
                return db.collection(collectionName).insertMany(fixtureData);
            }).then(function (result) {
                _.forEach(result.insertedIds, function (value, idx) {
                    fixtureData[idx]._id = value;
                });
                return db;
            });
    }).then(function (db) {
        db.close();
        return fixtureData;
    });
};
 
 我使用jasmine进行测试，我在每个beforeEach调用它，以便始终以相同的情况开始每个测试。 
 
 然后我有一个函数来测试删除（simplyfing）： 
 
var dataToDelete = fixtureData[0];
sut.deleteDocument(dataToDelete_.id)
    .then(function(result) {
        expect(....);
    });
 
 在我的deleteDocument里面，我什么都不做： 
 
db.collection('myCollection').deleteOne({ _id: theId })
    then(function(result)) {
        if (result.deletedCount === 0) {
            throw new Error('No document to delete with ID: ' + _id);
        }
        return null;
    });
 
 这里的theId变量是通过一个非常简单的函数在mongo ObjectId转换为id作为参数传递的： 
 
function (id) {
    if (_.isString(id)) {
        return MongoDb.ObjectId(id);
    }
    if (MongoDb.ObjectId.isValid(id) === true) {
        return id;
    }
    throw new Error('Invalid ObjectId');
};
 
 我正在使用mongodb Node.js驱动程序版本2.2.16 。 
 
 这里的问题是，如果我使用ObjectId作为_id ，我总是会收到deletedCount = 0 ，但如果我将它转换为String，它就可以工作并删除该函数。 
 
 这完全困扰我，因为我发现的每个文档和每个示例总是说_id是ObjectId 。 
 
 有人可以解释发生了什么吗？ 
 
 编辑:(答案让我朝着正确的方向前进，但如果您最终遇到这种情况，这是您正在寻找的实际答案）如果您在这种情况下最终在创建文档时在_id字段中传递字符串。 找出为什么你这样做，如果它不打算，你会解决它 

I'm trying to write test (spec) on a mongo DB wrapper and stumbled on this weird issue.
 
My code, build on top of a thin wrapper of mongodb, expose _id as string to the world but use (convert) them to ObjectId when talking to mongo.
 
I've an helper creating fixtures:
 
var _ = require('lodash'),
    Promise = require('bluebird'),
    MongoDb = require('mongodb');

var fixtureData = [
    {
        'uuid': '1',
        'owner': 'A',
        'data': 'someData1'
    },
    {
        'uuid': '2',
        'owner': 'A',
        'data': 'someData2'
    },
    {
        'uuid': '3',
        'owner': 'B',
        'data': 'someData3'
    },
    {
        'uuid': '4',
        'owner': 'A',
        'data': 'someData4'
    },
    {
        'uuid': '5',
        'owner': 'A',
        'data': 'someData5'
    },
    {
        'uuid': '6',
        'owner': 'B',
        'data': 'someData6'
    }
]

module.exports.loadFixtures  = function (url, collectionName) {
    var MongoClient = MongoDb.MongoClient;

    return MongoClient.connect(url, {
        promiseLibrary: Promise
    }).then(function (db) {
        return db.dropCollection(collectionName)
            .catch(function (err) {
                if (err.message === 'ns not found') {
                    return 'does not exist';
                }
                throw err;
            })
            .then(function () {
                return db.collection(collectionName).insertMany(fixtureData);
            }).then(function (result) {
                _.forEach(result.insertedIds, function (value, idx) {
                    fixtureData[idx]._id = value;
                });
                return db;
            });
    }).then(function (db) {
        db.close();
        return fixtureData;
    });
};
 
I use jasmine to test and I call this at every beforeEach to always start each test with the same exact situation.
 
I then have a function to test the delete (simplyfing):
 
var dataToDelete = fixtureData[0];
sut.deleteDocument(dataToDelete_.id)
    .then(function(result) {
        expect(....);
    });
 
Inside my deleteDocument I do nothing special:
 
db.collection('myCollection').deleteOne({ _id: theId })
    then(function(result)) {
        if (result.deletedCount === 0) {
            throw new Error('No document to delete with ID: ' + _id);
        }
        return null;
    });
 
The theId variable here is obtained converting in a mongo ObjectId the id passed as parameter with a very simple function:
 
function (id) {
    if (_.isString(id)) {
        return MongoDb.ObjectId(id);
    }
    if (MongoDb.ObjectId.isValid(id) === true) {
        return id;
    }
    throw new Error('Invalid ObjectId');
};
 
I'm using mongodb Node.js driver version 2.2.16.
 
The problem here is that I ALWAYS receive a deletedCount = 0 if I use an ObjectId as _id but if I covert it to String it works and delete the function.
 
This completely puzzle me because every documentation I've found and every example always say _id is a ObjectId.
 
Can someone explain what's going on?
 
EDIT: (the answer got me in the right direction but this is the actual anwer you are looking for if you end up in this situation) if you end up in this situation you are passing strings in the _id field when creating the document. Find out why you do that if it is not intended and you'll fix it

原文：https://stackoverflow.com/questions/41228499