为什么我的MongooseJS ObjectIds未能通过相等性测试? [英] Why do my MongooseJS ObjectIds fail the equality test?

问题描述

假设我按如下方式保存和检索相同的对象

Suppose I save and retrieve identical objects as follows

var obj1, obj2;

instance.save(function(err, saved) {
    obj1 = saved;
});

Model.find(obj1._id).run(function(err, retrieved) {
    obj2 = retrieved;
});

当我打印到控制台时，ObjectId是相同的.如果我在两个ObjectId上调用toString，它们是相等的.但是直接进行

When I print to the console, ObjectIds are the same. If I call toString on both ObjectIds they are equal. However doing a straight

obj1._id == obj2._id

返回false.这是怎么回事?

Returns false. What is happening here?

推荐答案

ObjectId是对象，因此标准==相等性测试将比较引用的相等性，而不是所包含的id值.比较它们的值的正确方法是将ObjectId.equals用作:

ObjectIds are objects so a standard == equality test is comparing the references for equality, not the contained id values. The right way to compare their values is to use ObjectId.equals as:

obj1.equals(obj2)

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