Today this article will see how to write a query using MongoDB Node.js to replace string or substring In a Document

We will replace a string in the Mongo document with the input string using a simple and easy approach i.e using $replaceOne aggregation operator which is supported in MongoDB v4.0 onwards.

We will cover below aspects,

We already looked at a simple way of adding or updating a new field to the document in our previous MongoDB sample series.

Getting started -MongoDB Node.js to Replace String

Here below is a sample schema or document we shall use,

Node.js – Replace Substring in MongoDB using replaceOne Aggregator

We are going to use a newly introduced aggregate operator to replace easily a string with matching criteria with part of the string.

Query Pattern Replace using $replaceOne

{ 
$replaceOne: { 
    input: <expression>, 
    find: <expression>, 
    replacement: <expression>}
}

In the above query,

You can replace the existing Mongo field using any other fields from the document using the above approach + using the approach discussed here.

Node.js Example using $replaceOne

In the below example, we will replace “total-order” with “order” in the mongo field.

Please add below using namespace

import { MongoClient } from 'mongodb';

Define the Regex query for the matching string,

'Link': {     
     '$regex': new RegExp('total-order')   
 }

Define the Set using replaceOne Operator,

'$set': {
      'Link': {
        '$replaceOne': {
          'input': '$Link', 
          'find': 'total-order', 
          'replacement': 'order'
        }
      }
    }

Example

const filter = {
  'Link': {
    '$regex': new RegExp('total-order')
  }
},[
  {
    '$set': {
      'Link': {
        '$replaceOne': {
          'input': '$Link', 
          'find': 'total-order', 
          'replacement': 'order'
        }
      }
    }
  }
];
const client = await MongoClient.connect(
  'mongodb://host/',
  { useNewUrlParser: true, useUnifiedTopology: true }
);

const coll = client.db('TheCodeBuzz').collection('Orders');
const cursor = coll.find(filter);
const result = await cursor.toArray();
await client.close();

Below is the schema post-update,

That’s all! Happy coding!

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Today, in this article will cover Node.js – MongoDB Date Time query with examples.

We will see how to get records using a date filter like ‘greater than’ OR ‘less than’ or get the records between 2 dates.

We will use the MongoDB Node.js Driver package to install the Mongo driver and query MongoDB.

For more details – https://mongodb.github.io/node-mongodb-native

We will cover the below aspects in today’s article,

Getting started

Here below is a sample schema or document we shall use for the date range query,

Install Node.js MongoDB driver

Please install the Node.js MongoDB driver package to get support for the MongoClient connection class and properties.

For more details visit- https://mongodb.github.io/node-mongodb-native

Add MongoDB Import statements

Please add below using namespaces

import { MongoClient } from 'mongodb';

Define MongoDB Connection

Using MongoClient class define the MongoDB Connection

const client = await MongoClient.connect(
  'mongodb://your server:27017/',
  { useNewUrlParser: true, useUnifiedTopology: true }
);

Here we will be using the below query to get the documents between two dates in MongoDB Collection.

Node.js- Mongo Date greater than query (‘gt’)

Define the date

const queryDate = new Date('2023-11-01');

Define the filter

Lets define the date filter as below,

const filter = {
  'DateAdded': {
    '$gt': queryDate

  }
};

Get the results

const coll = client.db('TheCodeBuzz').collection('Books');

const cursor = coll.find(filter);

const result = await cursor.toArray();

await client.close();

Complete sample code,

import { MongoClient } from 'mongodb';

# Define Node Mongo Connection

const client = await MongoClient.connect(
  'mongodb://your server:27017/',
  { useNewUrlParser: true, useUnifiedTopology: true }
);

# define date for the query 

const queryDate = new Date('2023-11-01');

# define filter for the query 

const filter = {
  'DateAdded': {
    '$gt': queryDate

  }
};


const coll = client.db('TheCodeBuzz').collection('Books');
const cursor = coll.find(filter);
const result = await cursor.toArray();
await client.close();

Mongo Atlas UI

The above query produces the same result as indicated below using ATLAS UI,

Node js- Mongo Date less than query (‘lt’)

Let’s define Node.js Mongo Datetime less than query (‘lt’)

# define date for the query 


const queryDate = new Date('2023-11-01');

# define filter for the query 

const filter = {
  'DateAdded': {
    '$lt': queryDate

  }
};

Node js- Mongo Date less than and greater than date query

# define date for the query 

const queryStartDate = new Date('2023-11-01');
const queryEndDate = new Date('2024-01-01');


# define filter for the query 

filter =  {
         'DateAdded': {
                '$gte': queryStartDate,
                '$lt': queryEndDate

         }
  }

For more details on queries where no date field in the schema is available , please visit this article,

• Query MongoDB using ObjectId by Date -MongoShell

That’s all! Happy coding!

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Do you have any better solutions or suggestions? Please sound off your comments below.

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Today this article will see how to write a MongoDB nested array string field value length query.

Today in this article, we will cover below aspects,

We will cover below query types,

• Greater than field value length

• Less than field value length

• Equal to the length of the field value

We shall see examples for MongoDB field query where we will get the records based on field length value greater than or less than of specified value. We will run field-length queries using CLI or Compass UI.

We already looked at a simple way of adding or updating a new field to the document in our previous MongoDB sample series.

We shall also see how to create a similar query using other languages like C# mongo driver.

Getting started

Here below is a sample schema or document we shall use for array object with field length query and will cover less than or greater than length query for field value “Books.category.value” field.

Below by value field is of type string and we will get all records where such field length is less than or greater than the specified size.

Mongo field length query using Mongo Shell or Compass UI

Here we will be using the below query to get the documents based on the value of the length of fields in the MongoDB Collection.

Nested array element finding and then getting its length can be done easily using below simple query as explained.

Pattern:

{
  "$expr": {
    "$anyElementTrue": {
      "$map": {
        "input": {
          "$reduce": {
            "input": "$<YourFieldName(fully qualified field)>",
            "initialValue": [],
            "in": { "$concatArrays": [ "$$<YourFieldName>", "$$this" ] }
          }
        },
        "in": { "$gte": [ { "$strLenCP": "$$this" }, <size of array>] }
      }
    }
  }
}

Where <YourFieldName> is the Mongo Field Name whose value length needs to be calculated.

MongoDB nested array string field value greater than query >

Below is the MongoDB string field value length greater than the query.

Example

In the below query, we get records where the field exists and the field length is greater than 5 characters in size.

MongoDB nested Array field string value length less than query <

Below is the mongo Shell query for less than dates.

Query Pattern

Replace in the above query,

 "in": { "$lte": [ { "$strLenCP": "$$this" }, <size of array>] }

MongoDB nested Array field string value length Equal to length =

Below is the mongo Shell query for equal to length query.

Query Pattern

Replace in the above query,

 "in": { "$eq": [ { "$strLenCP": "$$this" }, <size of array>] }

Using Regex – MongoDB nested array string field value length query

For more details on this approach please visit:

• Using Regex – MongoDB array string field value length query

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Today in this article we will see how to perform MongoDB – Query for documents array size greater than 1 or more.

Recently I was trying to find all the records where the array field has more than 1 entry.

After the initial trivial, I found there is no direct query but was able to find a query that helped me address this requirement easily.

Today in this article, we will cover below aspects,

Below is a sample JSON where array order is defined as an array type.

{
  "_id": "617f1b826cbcd5cf388e44f7",
  "Ssn": {
    "$binary": "AQN8wobDt3M8SsOPwrjDsHNVw5Ymwo3DlQJ1AQpYwrhyw6oIwp/CgAzCpCHDqcKBwrDCjTo+w4/CsMO0wozDmmfCuxE7w4tywofDoR/DhMOgw6HDhsKZwoRLwovCu8KDXQTCncKbL11nwpRQBMKeTcKLFlXCvwYxwrxUwoo=",
    "$type": "0"
  },
  "City": "NY",
  "Country": "USA",
  "States": "NY",
  "Zip": "12345",
  "order":  [ "name1",  "name2", "name3" ],
  "Name": "John"
}

Array order has 1 to 3 items in the collection.

We will build a query to find all the items where the array size is greater than 1.

Approach I – MongoDB Query using the not-equal operator

Command

{<array field>: {$type:'array', $ne: [] }}

Example

{order: {$type: 'array', $ne: []}}

The above query confirms if the array element has at least 1 or more records.

In our above example, The below query gives us results for array size 1 or 2 as below,

Approach II – MongoDB Query for documents array size is greater than 0 or 1 or 2

Query – MongoDB array documents with a count greater than1

{'order.0': {$exists: true}}

The above query will return all the records where the array size is greater than or equal to 1

Get MongoDB array documents with a count greater than 2

{'order.1': {$exists: true}}

The above query will return all the records where the array size is greater than or equal to 2

References:

• MongoDB Case-sensitive query examples

• Getting Started MongoDB in .NET Core with Examples

Do you have any comments or ideas or any better suggestions to share?

Please sound off your comments below.

Happy Coding !!

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Today in this article, we shall see how to Add Swagger OpenAPI in Node.js and Express API. Swagger or OpenAPI describes the standards and specifications for the RESTFul API description.

These specifications are an attempt to create a universal and language agnostic description for describing the REST API.

In this article, we shall see below overall aspects,

Node.js express API can use OpenAPI V3.0 specifications which are more generic guidelines and specifications around how the API documentation should be generated.

Swagger provides the advantage of understanding and consuming the RESTFule API (for developers ).

Getting started – Add Swagger OpenAPI in Node.js

Add Swagger OpenAPI in Node.js is easy and can be performed using below high-level steps discussed,

Create your Node + Express project and perform NPM install.

Install node package called swagger-ui-express using NPM as below,

npm install swagger-ui-express --save

Install node package called swagger-jsdoc using NPM as below,

npm install swagger-jsdoc --save

Please enable the Swagger module in the API pipeline,

Enable Swagger module’s in the API pipeline in App.js as below,

const swaggerUi = require("swagger-ui-express");

const swaggerJsondoc = require("swagger-jsdoc");

Let’s define a simple GET API

Let’s define a simple GET API that returns a string as a response to the request.

Add below GET method in the App.js as below,

app.get("/hello", (req, res) => {
  res.json("Hello world!");
});

Add API level Global metadata

API level global data can be defined using Info object with details like Title, Version, or Description details.

Below is the list of API level documentation elements that can be specified,

• Title

• Version

• Description

• Contact

• License details

const options = {
  swaggerDefinition: {
    openapi: "3.0.0",
    info: {
      title: "TheCodebuzz API",
      version: "1.0.0",
      description:
        "Thecodebuzz test service to demo how to document your API",
      license: {
        name: "MIT",
        url: "https://www.thecodebuzz.com"
      },
      contact: {
        name: "TheCodeBuzz",
        url: "https://www.thecodebuzz.com",
        email: "info@thecodebuzz.com"
      }
    },
    servers: [
      {
        url: "http://localhost:3000/"
      }
    ]
  },
  apis: []
};

Add Swagger UI Setup

Add Swagger UI as middleware in the express API pipeline.

const specs = swaggerJsondoc(options);
app.use("/docs", swaggerUi.serve);


app.get(
  "/docs",
  swaggerUi.setup(specs, {
    explorer: true
  })
);

Launch Swagger URL

Swagger URL can be launched here by using http://localhost:3000/docs

Add REST method level description

Let’s define api-method-docs.js which contains the REST method description as per the supported schema of Swagger/OpenAPI v3.0.

/**
 * @swagger
 * tags:
 *   name: Hello
 *   description: Greetings API from TheCodeBUzz
 */

/**
 * @swagger
 * path:
 *  /hello:
 *    get:
 *      summary: Get greeting message from TheCodebuzz
 *      responses:
 *        "200":
 *          description: GET reponse from API
 *          content:
 *            application/json:
 *              schema:
 *                type: string
 */

Above API level description can be defined in the api-method-doc.js as below,

  apis: ["./ api-method-doc.js"]

Please see below updated data,

const options = {
  swaggerDefinition: {
    openapi: "3.0.0",
    info: {
      title: "TheCodebuzz API",
      version: "1.0.0",
      description:
        "Thecodebuzz test service to demo how to document your API",
      license: {
        name: "MIT",
        url: "https://www.thecodebuzz.com"
      },
      contact: {
        name: "TheCodeBuzz",
        url: "https://www.thecodebuzz.com",
        email: "infoATthecodebuzz.com"
      }
    },
    servers: [
      {
        url: "http://localhost:3000/"
      }
    ]
  },
  apis: ["./api-doc.js"]
};

Please relaunch your API with the above changes.

Once launched, you shall see the GET method level API description below,

Let’s execute the GET API from Swagger UI. You see Swagger GET API returns your expected result.

That’s All.

Now you can use the above technique to add API documentation for POST, PUT, DELETE methods as required.

References:

• Angular Architecture and Design Guidelines

• Swagger 3.0 example (OpenApi 3.0 sample example)

That’s all! Happy coding!

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Do you have any better solutions or suggestions? Please sound off your comments below.

Summary

Its simple to enable Swagger OpenAPI documentation in the Node js. Good API documentation helps reduce dependencies and provides the advantage of understanding the REST API(for developers) consuming API. It provides easy-ready API documentation and providing details of the capabilities a service/API provides.

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