比较猫鼬 _id 和字符串

问题描述

我有一个 node.js 应用程序，它提取一些数据并将其粘贴到一个对象中，如下所示:

I have a node.js application that pulls some data and sticks it into an object, like this:

var results = new Object();

User.findOne(query, function(err, u) {
    results.userId = u._id;
}

当我根据存储的 ID 执行 if/then 时，比较永远不会为真:

When I do an if/then based on that stored ID, the comparison is never true:

if (results.userId == AnotherMongoDocument._id) {
    console.log('This is never true');
}

当我执行两个 ID 的 console.log 时，它们完全匹配:

When I do a console.log of the two id's, they match exactly:

User id: 4fc67871349bb7bf6a000002 AnotherMongoDocument id: 4fc67871349bb7bf6a000002

我假设这是某种数据类型问题，但我不确定如何将 results.userId 转换为将导致上述比较为真的数据类型，而我的外包大脑(又名 Google)无法帮助.

I am assuming this is some kind of datatype problem, but I'm not sure how to convert results.userId to a datatype that will result in the above comparison being true and my outsourced brain (aka Google) has been unable to help.

推荐答案

Mongoose 使用 mongodb-native 驱动程序，它使用自定义 ObjectID 类型.您可以使用 .equals() 方法比较 ObjectID.以您的示例，results.userId.equals(AnotherMongoDocument._id).ObjectID 类型还有一个 toString() 方法，如果您希望以 JSON 格式或 cookie 存储 ObjectID 的字符串化版本.

Mongoose uses the mongodb-native driver, which uses the custom ObjectID type. You can compare ObjectIDs with the .equals() method. With your example, results.userId.equals(AnotherMongoDocument._id). The ObjectID type also has a toString() method, if you wish to store a stringified version of the ObjectID in JSON format, or a cookie.

如果你使用 ObjectID = require("mongodb").ObjectID(需要 mongodb-native 库)你可以检查 results.userId 是否是一个有效的标识符results.userId instanceof ObjectID.

If you use ObjectID = require("mongodb").ObjectID (requires the mongodb-native library) you can check if results.userId is a valid identifier with results.userId instanceof ObjectID.

等

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