过滤 mongodb 和 nodejs 中的文档

Question

数据库中的数据存储如下。 如果我做这样的查询

const food = await Nutrition.find()

然后我得到这个作为回应

[
  {
    _id: 6035ff4778b1893fa5e8080f,
    name: 'apple',
    weight: 100,
    unit: 'gram',
    carbohydrates: 14,
    calories: 52,
    proteins: 0.3,
    fats: 0.2,
    __v: 0
  },
  {
    _id: 6036011437035541b0bd5e0a,
    name: 'banana',
    weight: 100,
    unit: 'gram',
    carbohydrates: 23,
    calories: 89,
    proteins: 11,
    fats: 0.39,
    __v: 0
  },
  {
    _id: 6036011437035541b0bd5e0b,
    name: 'melon',
    weight: 100,
    unit: 'gram',
    carbohydrates: 45,
    calories: 100,
    proteins: 11,
    fats: 0.39,
    __v: 0
  }
]

我在nodejs中有这个controller，它从数据库中获取食物营养

const Nutrition = require('../model/nutritionalFacts')

exports.nutritionFacts = (async (req,res) =>{
    try {
        const food = await Nutrition.find()
        console.log(food);
    } catch (error) {
        console.log('Error occurred',error.message);
    }
})

现在在请求（req）中，req.body 将作为

[
  { name: 'apple', id: 0, selected: true, weight: 100, unit: 'gram' },
  { name: 'banana', id: 1, selected: true, weight: 100, unit: 'gram' }
]

现在，我只想使用 MongoDB 查询语法，只过滤数据库中名称与来自客户端的对象数组中的名称匹配的那些文档，而无需循环。 我们可以这样做吗？

Answer 1

您可以使用$in运算符来实现这一点。 您需要更改您的查找方法如下

var namesArr = ["banana", "melon"];
db.Nutrition.find({ "name" : { "$in": namesArr } })

然后是上面示例的结果：

{
        "_id" : ObjectId("60361058cce08c8b8ebe0509"),
        "name" : "banana",
        "weight" : 100,
        "unit" : "gram",
        "carbohydrates" : 23,
        "calories" : 89,
        "proteins" : 11,
        "fats" : 0.39,
        "__v" : 0
}
{
        "_id" : ObjectId("60361058cce08c8b8ebe050a"),
        "name" : "melon",
        "weight" : 100,
        "unit" : "gram",
        "carbohydrates" : 45,
        "calories" : 100,
        "proteins" : 11,
        "fats" : 0.39,
        "__v" : 0
}

Answer 2

尝试这个

const Nutrition = require('../model/nutritionalFacts');

exports.nutritionFacts = (async (req, res) => {
  try {

    if (!Array.isArray(req.body.payload)) {
      throw new Error("Invalid payload!") // or whatever error message u want!
    }

    const names = payload.map(item => item.name); // u cannot avoid this looping of payload!

    const conditions = {
      name: { $in: names }
    };

    const food = await Nutrition.find(conditions);
    console.log(food);
  } catch (error) {
    console.log('Error occurred', error.message);
  }
})