将项目推送到Mongodb集合数组

问题描述

我试图将一个值推入mongodb集合arrayList(user.completed)，但是即使我的代码似乎正确，它也没有得到更新.

I am trying to push a value to mongodb collection arrayList (user.completed) but it's not getting updated even though my code seems correct.

当我进行API调用时，将传递值，但是"$ push"不会为完成的数组添加值！我在这里想念什么?

When I make the API call, the values are being passed however "$push" isn't adding value to completed array!! What am I missing here?

当我尝试将值推送到字符串时，出现猫鼬错误，正如预期的那样.但是，当我尝试将值推入未定义的键('abc')时，不会像mongodb文档建议的那样创建新数组！不知道这是怎么回事！

When I try to push to value to a string, I get mongoose error as expected. But when I try to push value to an undefined key ('abc'), a new array doesn't get created like the mongodb documentation suggest! Not sure what is going on here!

//Mongodb数据

// Mongodb Data

{
"_id" : ObjectId("58aa2eb1de7b414237b93981"),
"email" : "[email protected]",
"firstName" : "test",
"completed" : [],
"playing" : [],
"__v" : 2

//API

import mongoose from 'mongoose'
import { Router } from 'express'
import User from './../model/user'

api.put('/completed/:id', (req, res) => {
    User.update(
        { "_id": req.params.id },
        { "$push": {
             "completed": req.body.completed
        }}
    )
    .then(doc => res.send(doc), err => res.status(400).send(err))
})

//请求

var request = require("request");

var options = {
    method: 'PUT',
    url:    'http://localhost:8008/v1/user/completed/58aa2eb1de7b414237b93981',
    headers: {
        'content-type': 'application/json' },
        body: { completed: { game: 'A', player: 'B' } },
        json: true
     };

    request(options, function (error, response, body) {
        if (error) throw new Error(error);
        console.log(body);
    });

推荐答案

使用$addToSet停止复制数组中的相同数据

use $addToSet to stop duplication of same data in the array

$addToSet不会将项目添加到给定字段中，如果它已经包含该项目，但是$push会将给定值添加到字段中，无论该项目是否存在.

$addToSet won't add the item to the given field if it already contains it, but $push will add the given value to field whether it exists or not.

User.update({ "_id": req.params.id  },
    { $addToSet: { "completed": req.body.completed } }, function (err, d) {
        if (!d.nModified) {
           // same value entered won't add to the array
        } else {
            // new value entered and will add to the array
        }
});

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