猫鼬:findOneAndUpdate不返回更新的文档

本文介绍了猫鼬:findOneAndUpdate不返回更新的文档的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

下面是我的代码

var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/test');

var Cat = mongoose.model('Cat', {
    name: String,
    age: {type: Number, default: 20},
    create: {type: Date, default: Date.now}
});

Cat.findOneAndUpdate({age: 17}, {$set:{name:"Naomi"}},function(err, doc){
    if(err){
        console.log("Something wrong when updating data!");
    }

    console.log(doc);
});

我的mongo数据库中已经有一些记录，我想运行此代码来更新年龄为17岁的姓名，然后在代码末尾打印出结果.

I already have some record in my mongo database and I would like to run this code to update name for which age is 17 and then print result out in the end of code.

但是，为什么我仍然从控制台获得相同的结果(而不是修改后的名称)，但是当我转到mongo db命令行并键入"db.cats.find();"时.结果带有修改后的名称.

However, why I still get same result from console(not the modified name) but when I go to mongo db command line and type "db.cats.find();". The result came with modified name.

然后我再次运行此代码，并修改了结果.

Then I go back to run this code again and the result is modified.

我的问题是:如果修改了数据，那么为什么在console.log上还是第一次获得原始数据.

My question is: If the data was modified, then why I still got original data at first time when console.log it.

为什么会这样?

默认是返回未更改的原始文档.如果要返回更新后的新文档，则必须传递一个附加参数:new属性设置为true的对象.

Why this happens?

The default is to return the original, unaltered document. If you want the new, updated document to be returned you have to pass an additional argument: an object with the new property set to true.

从猫鼬文档:

Model.findOneAndUpdate(conditions, update, options, (error, doc) => {
  // error: any errors that occurred
  // doc: the document before updates are applied if `new: false`, or after updates if `new = true`
});

可用选项

new:bool-如果为 true ，则返回经过修改的文档，而不是原始文档. 默认为假(已在4.0中更改)

new: bool - if true, return the modified document rather than the original. defaults to false (changed in 4.0)

解决方案

如果要在doc变量中更新结果，请通过{new: true}:

Solution

Pass {new: true} if you want the updated result in the doc variable:

//                                                         V--- THIS WAS ADDED
Cat.findOneAndUpdate({age: 17}, {$set:{name:"Naomi"}}, {new: true}, (err, doc) => {
    if (err) {
        console.log("Something wrong when updating data!");
    }

    console.log(doc);
});

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