Find and print elements name with MongoDB and Mangoose with Node.js then disconnect to the server-CodePudding

I'm using mongoDB with mongoose I created a fruit collection and I want to print the fruits names then disconnect to the server

const mongoose = require('mongoose');
mongoose.connect("mongodb://localhost:27017/fruitsDB", {
  useNewUrlParser: true
});

const fruitSchema = new mongoose.Schema({ //schema: come vogliamo che gli eleemnti vengano sturtturati
  name: String,

  rating: {
    type: Number,
    min: 1,
    max: 10
  },
  review: String
});

//creiamo un modulo
const Fruit = mongoose.model("Fruit", fruitSchema);

const fruit = new Fruit({
  name: "Apple",
  rating: 8,
  review: "good"
});
//fruit.save();
const kiwi = new Fruit({
  name: "Kiwi",
  rating: 10,
  review: "great"
});

Fruit.find(function(err, fruits) {
  if (err) {
    console.log(err);
  } else {
    mongoose.connection.close();
    fruits.forEach(function(fruit) {
      console.log(fruit.name);
    });
  }
});

I've written this in the app.js then I compiled it with the command "node app.js" The terminal gives me this:

Apple Apple Apple Apple Kiwi

(node:24352) UnhandledPromiseRejectionWarning: MongoExpiredSessionError: Cannot use a session that has ended at Object.applySession (C:\Users\Feder\Desktop\udemy\mongooseFruit\node_modules\mongoose\node_modules\mongodb\lib\sessions.js:647:16) at Connection.command (C:\Users\Feder\Desktop\udemy\mongooseFruit\node_modules\mongoose\node_modules\mongodb\lib\cmap\connection.js:185:36) at C:\Users\Feder\Desktop\udemy\mongooseFruit\node_modules\mongoose\node_modules\mongodb\lib\sdam\server.js:176:18 at Object.callback (C:\Users\Feder\Desktop\udemy\mongooseFruit\node_modules\mongoose\node_modules\mongodb\lib\cmap\connection_pool.js:266:13) at C:\Users\Feder\Desktop\udemy\mongooseFruit\node_modules\mongoose\node_modules\mongodb\lib\cmap\connection_pool.js:474:29 at C:\Users\Feder\Desktop\udemy\mongooseFruit\node_modules\mongoose\node_modules\mongodb\lib\cmap\connection_pool.js:402:13 at callback (C:\Users\Feder\Desktop\udemy\mongooseFruit\node_modules\mongoose\node_modules\mongodb\lib\cmap\connect.js:52:9) at C:\Users\Feder\Desktop\udemy\mongooseFruit\node_modules\mongoose\node_modules\mongodb\lib\cmap\connect.js:124:13 at MessageStream.messageHandler (C:\Users\Feder\Desktop\udemy\mongooseFruit\node_modules\mongoose\node_modules\mongodb\lib\cmap\connection.js:479:9) at MessageStream.emit (events.js:400:28) (Use node --trace-warnings ... to show where the warning was created) (node:24352) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag --unhandled-rejections=strict (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1) (node:24352) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

CodePudding user response：

First of all you need to save your models to database first.

Second of all looks like you are using the find method in wrong way.

const fruit = new Fruit({
  name: "Apple",
  rating: 8,
  review: "good"
});

fruit.save();

const kiwi = new Fruit({
  name: "Kiwi",
  rating: 10,
  review: "great"
});

kiwi.save();

Fruit.find({}).then((fruits) => {         
    mongoose.connection.close();
    fruits.forEach(function(fruit) {
      console.log(fruit.name);
    });
});

Also I would suggest to use async/await to improve code readability.

CodePudding user response：

You can try something like that:

const fruits = await Fruit.find({})
// do whatever you want with fruits
mongoose.connection.close();

It looks like you are trying to close the connection while still using it. By using await you're gonna wait that the query is over before closing the connection.