Mongoose Queries Model.deleteOne() API

Mongoose module is one of Node.js’s most potent external modules. To transfer the code and its representation from MongoDB to the Node.js server, Mongoose is a MongoDB ODM (Object Database Modelling) tool.

The deleteOne() function is used to delete the first document which matches the condition.

Syntax:

deleteOne(conditions, options)

Parameters:

• conditions: The filter conditions.
• options: The options object.

Returns: An object with the count of deleted documents.

Installation of mongoose module:

Step 1: You can install this package by using this command.

npm install mongoose

Step 2: After installing the mongoose module, you can check your mongoose version in command prompt using the command.

npm version mongoose

Step 3: After that, you can just create a folder and add a file, for example, index.js. To run this file you need to run the following command.

node index.js

Following is the dataset, I am using in the following examples.

Example 1: In this example, we are trying to delete a document with _id=11. As there is no such document in the data we are using, hence no document will be deleted.

Javascript

const Person = require("../mongoose/model/person");
const mongoose = require("mongoose");

let mongoDB = mongoose.connect
    ("mongodb://localhost:27017/person", {
    useNewUrlParser: true,
    useUnifiedTopology: true,
});

let db = mongoose.connection;
db.on("error", console.error.bind(console,
    "MongoDB Connection Error"));

(async () => {
    const res = await Person.deleteOne(
        { _id: 11 },
    );
    console.log(`Number of Deleted Documents: ${res.deletedCount}`);
})();

Output:

Example 2: In this example, we are trying to delete a document with last_name=Bourgeois. As there is a document that matches the condition, it will be deleted.

Javascript

const Person = require("../mongoose/model/person");
const mongoose = require("mongoose");

let mongoDB = mongoose.connect
    ("mongodb://localhost:27017/person", {
    useNewUrlParser: true,
    useUnifiedTopology: true,
});

let db = mongoose.connection;
db.on("error", console.error.bind(console, "
    MongoDB Connection Error"));

(async () => {
    const res = await Person.deleteOne
        ({ last_name: "Bourgeois" });
    console.log(`Number of Deleted Documents:
        ${res.deletedCount}`);
})();

Output:

Reference: https://mongoosejs.com/docs/api/model.html#model_Model-deleteOne