The skill set of MEAN stack developers to manage both the front-end and back-end of apps in a consistent JavaScript-based environment makes them valuable to companies. The demand for web development solutions that are economical, scalable, and efficient is what is driving this demand. Hence, acquiring skills with MongoDB, Express.js, Angular.js, and Node.js becoming essential. Learn through them with this MEAN Stack Tutorial. Get started with our MEAN Stack course syllabus.
MEAN Stack Basics
Companies frequently use the MEAN stack because of its cost-effectiveness and capacity for quick development. The MEAN stack is thought to be chosen by a sizable portion of new tech businesses. We cover all important concepts in this MEAN Stack complete tutorial.
Foundational Technologies
Below are the basic elements of MEAN Stack:
MongoDB
NoSQL: A subset of database management systems known as “Not Only SQL,” or NoSQL, is distinct from the more conventional Relational Database Management Systems (RDBMS).
NoSQL databases use flexible schemas and a variety of data models that are tailored to particular requirements rather than following a strict, schema-based structure with tables, rows, and columns.
Uses of NoSQL:
- Handling Big Data: Large amounts of unstructured, semi-structured, and structured data can be handled and processed by NoSQL databases.
- Scalability and Performance: They can effectively manage large traffic and data loads because of their horizontal scalability.
- Agile Development: Quicker iterations and simpler adaptation to shifting requirements are made possible by the flexible schemas’ good alignment with agile development processes.
- Needs of Modern Apps: NoSQL databases frequently more naturally accommodate the data structures (such JSON documents) utilized in contemporary web and mobile apps.
- Cost-Effectiveness: Compared to scaling up pricey proprietary RDBMS, growing horizontally on commodity hardware may be more economical.
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MongoDB: One well-known open-source, document-oriented NoSQL database is MongoDB. MongoDB stores data in flexible, JSON-like documents with dynamic schemas as opposed to typical relational databases, which store data in tables and rows.
Applications for MongoDB:
Due to its scalability and flexibility, MongoDB can be used for a variety of purposes, such as:
- Content Management Systems (CMS): Systems for managing and storing various kinds of content.
- E-commerce Platforms: keeping track of customer profiles, order details, and product catalogs.
- Real-time Analytics: Managing and evaluating massive amounts of streaming data.
- Internet of Things (IoT): Data from several devices is ingested and processed.
- Gaming Applications: Keeping track of leaderboards, game states, and player profiles.
- Mobile Applications: Offering a versatile backend for storing data on the go.
- Log Management and Analysis: Application logs are stored and examined.
- Customer Relationship Management, or CRM: Managing client information and communications.
- Social Networks: Keeping track of connections, material, and user profiles.
- Personalization Engines: storing information about user activity and preferences.
- Big Data Applications: Managing huge, unstructured databases.
MongoDB Installation and Setup
General Prerequisites:
- Sufficient Disk Space: Make sure your computer has enough free space for both storing your databases and downloading and installing MongoDB.
- Administrator Rights: To complete the installation, you’ll probably need administrator or sudo rights.
- Stable Internet Connection: A steady internet connection is required in order to download the installation files for MongoDB.
Installation Setup Based on Operating Systems:
- Windows: MongoDB may be installed on Windows using either the ZIP archive or the MSI installer. For ease of use, the MSI installer is typically advised.
- macOS: Using Homebrew, a macOS package manager, is the suggested method for installing MongoDB on macOS.
- Linux (Ubuntu, CentOS, etc.): The Linux installation procedure differs based on the distribution. MongoDB uses its package managers (such as apt for Debian/Ubuntu and yum for CentOS/RHEL) to give appropriate instructions for different Linux systems.
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Core Concepts of MongoDB
Here are the fundamental building blocks of MongoDB:
Database:
- Container for Collection: A database is a logical collection grouping. A single instance of the MongoDB server can house several databases.
- Logical Separation: Databases offer a means of classifying and separating various data sources. For an e-commerce application, for instance, you may have a database of users and a database of products.
- Default Databases: Some databases are included with MongoDB:
- admin: For user administration and administrative operations.
- config: For internal sharded cluster setup.
- local: Contains information about local instances and the replica set’s operation log (oplog).
- Database Operations: MongoDB commands allow you to create, drop, list, and switch between databases.
Collection:
- Grouping of Document: A collection is a collection of MongoDB documents. From a conceptual standpoint, it is similar to a relational database table.
- Schema-Less Nature: Documents in a collection don’t have to follow a rigid, predetermined schema, even if they are frequently related. As a result, data structures can change within the same collection.
- Naming Conventions: Strings that describe the data they contain (such as people, products, or orders) should be used as collection names. They are sensitive to case.
- No Fixed Structure: By default, MongoDB does not impose a uniform structure on all of the documents in a collection. If necessary, schema validation can be used to impose mandatory fields and particular data types.
Document:
- The Basic Unit: In MongoDB, the document serves as the basic data unit. Consider it a single record.
- JSON-like Structure: Documents follow the structure of JavaScript Object Notation, or JSON. Key-value pairs make up their composition.
- Dynamic Schema: Documents in a MongoDB collection may contain various fields and structures, in contrast to rows in a relational database table that have a set schema. This offers a great deal of versatility.
- Data Types: A document’s values may be any of the following BSON (Binary JSON) data types:
- String
- Number (Integer, Long, Double)
- Boolean
- Date (stored as milliseconds since the Unix epoch)
- Array
- Object (embedded documents)
- Null
- Binary data
- ObjectId
Example:
{
“_id”: ObjectId(“64567a89b123c4d5e6f78901”),
“name”: “Alice Smith”,
“age”: 30,
“email”: “alice.smith@example.com”,
“address”: {
“street”: “123 Main St”,
“city”: “Chennai”,
“zipcode”: “600001”
},
“hobbies”: [“reading”, “hiking”],
“isStudent”: false
}
Fields:
- Key-Value Pairs: A MongoDB document’s field is a key-value pair.
- Keys are Strings: A document’s keys are always strings.
- Case-Sensitive: Field names are case-sensitive; for example, name differs from name.
- Dot Notation: Dot notation, such as address.city, is used to access fields in embedded documents.
Review Your Skills: MongoDB Interview Questions and Answers.
CRUD Operations in MongoDB
Here are MongoDB’s basic CRUD (Create, Read, Update, Delete) functions. These are the fundamental steps you will take in order to work with your data. Here we use the Mongosh shell to demonstrate these actions and give examples based on a fictitious user collection utilizing documents such as these:
{
“_id”: ObjectId(“someObjectId1”),
“name”: “John Doe”,
“age”: 30,
“email”: “john.doe@example.com”
}
Create (Insert): The insertOne() and insertMany() methods are used to add new documents to a collection.
- insertOne() is used to add a single document.
db.users.insertOne({
name: “Alice Smith”,
age: 25,
email: “alice.smith@example.com”
})
- insertMany() is used to add multiple documents.
db.users.insertMany([
{ name: “Bob Johnson”, age: 40, email: “bob.johnson@example.com” },
{ name: “Eve Williams”, age: 22, email: “eve.williams@example.com” }
])
Read (Find): The find() method is used to retrieve documents from a collection.
- find() with no arguments: It returns every document that was collected.
db.users.find()
- find() with a query document: It returns papers that meet the predetermined standards.
db.users.find({ name: “John Doe” })
- findOne(): The first document that satisfies the query conditions is returned by the findOne() function. It returns null if no documents match.
db.users.findOne({ age: 40 })
Update: The updateOne(), updateMany(), and replaceOne() methods are used to change already-existing documents in a collection.
- updateOne(): The first document that satisfies the filter criteria is updated.
db.users.updateOne(
{ name: “John Doe” }, // Filter to identify the document(s) to update
{ $set: { age: 31 } } // Update operator to modify the ‘age’ field
)
Delete: The deleteOne() and deleteMany() methods are used to eliminate documents from a collection.
- deleteOne(): The first document that satisfies the filter criteria is deleted.
db.users.deleteOne({ name: “Eve Williams” })
- deleteMany(): It removes every file that meets the filter’s requirements.
db.users.deleteMany({ age: { $gte: 40 } })
Querying in MongoDB
The powerful and expressive query language (MQL) provided by MongoDB allows you to get the precise data you require.
The find() Method:
db.collection.find(<query>, <projection>) is the main technique for data querying.
- <query>: (Optional) A document outlining the standards by which documents are chosen. It returns every document in the collection if omitted or empty ({}).
- <projection>: (Optional) A document that indicates which fields should be included or left out of the documents that are returned.
// Find all users named “Alice Smith”
db.users.find({ name: “Alice Smith” })
// Find all users aged 30
db.users.find({ age: 30 })
// Find all users with the email “bob.johnson@example.com”
db.users.find({ email: “bob.johnson@example.com” })1
Query Operators:
To generate more intricate and focused queries, MongoDB offers a large variety of query operators. Usually, these operators have a dollar sign ($) before them. Some of them are:
- $eq: Finds values that are equivalent to a given number. (As demonstrated above, frequently implicit)
- $ne: Compares values that don’t match a given value.
db.users.find({ age: { $ne: 25 } })
- $gt: It matches values that exceed a given threshold.
db.users.find({ age: { $gt: 35 } })
- $gte: It matches values that are either higher or lower than a given value.
db.users.find({ age: { $gte: 30 } })
- $lt: It matches values that fall below a given threshold.
db.users.find({ age: { $lt: 25 } })
- $lte: It compares values that fall below or equal a given value.
db.users.find({ age: { $lte: 25 } })
- $in: It corresponds to any of the values listed in an array.
db.users.find({ age: { $in: [25, 40] } })
- $nin: It doesn’t match any of the array’s stated values.
db.users.find({ age: { $nin: [25, 40] } })
Indexing:
A tiny percentage of the collection’s data is stored in these unique data structures in an accessible format. By doing this, MongoDB can find documents that match a query fast without having to search across the full collection.
Improving Query Performance: MongoDB and relational database indexes are comparable.
Index on Any Field: Any field or group of fields in a document, including fields inside arrays and embedded documents, can have an index created on it.
Different Index Types: To optimize a range of query patterns, MongoDB provides a variety of index types, such as:
- Single Field Indexes
- Compound Indexes
- Multikey Indexes (for indexing arrays)
- Text Indexes (for full-text search)
- Geospatial Indexes (for location-based queries)
- Unique Indexes (to enforce uniqueness of field values)
Trade-offs: Because indexes must be updated whenever documents are added, modified, or removed, they can marginally impair write performance even while they enhance read performance.
Aggregation:
- Data Processing Pipeline: You can process and transform data using a series of steps using MongoDB’s aggregation framework.
- Stages: The pipeline’s stages each carry out a particular action on the data (for example, $match filters documents, $group groups documents based on a certain expression, $sort sorts documents, and $project reshapes documents).
- Complex Data Analysis: Aggregation is an effective tool for creating reports, analyzing complex data, and changing data for a variety of uses.
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Express.JS
A powerful collection of functionality for creating web and mobile applications is offered by Express.js, also known as just Express, a simple and adaptable Node.js web application framework.
Consider it as a collection of conventions and tools that simplify the development of server-side applications that are built on top of Node.js.
Core Concepts in Express.js:
- Request Object (req): It includes details about the incoming HTTP request, including the request body, query parameters, headers, and more.
- Response Object (res): It is used to return to the client the HTTP response. It offers ways to deliver data (HTML, JSON, etc.), set headers, and finish the response.
- Middleware: operations that take place during a request-response cycle. They have the ability to carry out operations, alter the req and res objects, terminate the cycle of requests and responses, or transfer control to the subsequent middleware function.
- Routing: Specifying the way in which the application reacts to client requests sent to particular HTTP methods and URL routes.
- Route Handlers: Functions that are carried out upon matching a particular route. They include the application logic needed to process the request and reply.
- Template Engines: It is used to embed server-side data into HTML templates in order to create dynamic HTML content.
- RESTful APIs: Creating and designing APIs in accordance with REST guidelines.
- HTTP methods and their semantic meaning.
- Status codes.
- Resource-based endpoints.
- Error Handling: Putting appropriate error handling procedures in place.
Simple Hello World in Express.JS
// 1. Import the Express.js module
const express = require(‘express’);
// 2. Create an Express application instance
const app = express();
// 3. Define a route for the root path (‘/’) and the GET HTTP method
app.get(‘/’, (req, res) => {
// 4. Send the “Hello World!” response to the client
res.send(‘Hello World!’);
});
// 5. Define the port the server will listen on
const port = 3000;
// 6. Start the server and listen on the specified port
app.listen(port, () => {
console.log(`Server listening at http://localhost:${port}`);
});
How to Run This:
- Verify that your system has both Node.js and npm (Node Package Manager) installed.
- Make a new directory called hello-express for your project.
- In your terminal, navigate to this directory.
- Set up a project in Node.js:
npm init -y
This will create a package.json file.
- Install the Express.js dependency:
npm install express
The Express.js library will be downloaded, installed, and added to your package.json file as a result.
- Paste the code above into a file called server.js, or any other name you like.
- Use your terminal to launch the application:
node server.js
- Open your browser and go to http://localhost:3000. The “Hello World!” message ought to appear.
Importing the module, establishing an app instance, specifying a route, processing the request, sending a response, and starting the server are the fundamental steps of an Express.js application that are illustrated in this straightforward example.
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Angular.JS
It is in charge of managing user interactions, data binding, the user interface, and backend API calls. Modules, controllers, services, directives, routing, and other AngularJS principles would be used to organize your application.
Installation and Setup:
Install the Angular CLI: An effective tool for creating, managing, building, testing, and deploying Angular apps is the Angular CLI. Run the following command globally in your terminal (command prompt on Windows, terminal on macOS/Linux):
npm install -g @angular/cli
# or using yarn:
# yarn global add @angular/cli
The ng command can be used from any directory because the -g flag installs the CLI globally on your system.
Check the Installation of the Angular CLI: You can confirm that the installation is finished by running:
ng version
The Angular CLI version and other pertinent details about your Angular setup will be shown by this command.
Create a New Angular Project: Use the cd command in your terminal to get to the directory where you wish to build your Angular project. Then, to create a new Angular application, execute the following command:
ng new client # You can replace ‘client’ with your desired project name
Navigate to Your Angular Project Directory: After the project creation process is finished, go to the project directory that was just created:
cd client
Serve Your Angular Application (Development Server): Use the following command from within your project directory to launch your Angular application on a development server:
ng serve -o
# or using yarn:
# yarn start
- ng serve launches a local development server and builds your application.
- With the optional -o switch, your Angular application will launch immediately at http://localhost:4200/ in your default web browser.
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Angular CLI will keep an eye on your project files for modifications while the server is operating. The program in your browser will automatically reload with the changes made when you save a modified file.
import { HttpClientModule } from ‘@angular/common/http’;
import { NgModule } from ‘@angular/core’;
import { BrowserModule } from ‘@angular/platform-browser’;
import { AppComponent } from ‘./app.component’;
@NgModule({
declarations: [
AppComponent
],
imports: [
BrowserModule,
HttpClientModule // Import the HttpClientModule
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
Core Concepts of Angular.JS
- Components: TypeScript classes, HTML templates, and CSS styles are the fundamental building blocks of an Angular application.
- Modules: Grouping related parts, services, and additional code together.
- Templates: The component structure of HTML.
- Data Binding: Data binding, which includes interpolation, property binding, event binding, and two-way binding, is the process of joining component data to the template.
- Directives: Including attribute and structural directives that add behavior to the DOM.
- Services: Components can be equipped with reusable logic.
- Dependency Injection: Angular’s method for providing and managing dependencies.
- Routing: Moving between the application’s many views.
- Forms: Reactive and template-driven forms for managing user input.
- HTTP Client: Requests are sent to backend APIs via the HTTP Client.
- Observables and RxJS: Asynchronous Data Streams.
- State Management: Angular Signals and NgRx, which are optional yet crucial for bigger applications.
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Node.JS
You can run JavaScript code outside of a web browser with the help of the Node.js runtime environment. JavaScript has historically been mostly utilized for front-end web development, which takes place in the user’s browser.
Because Node.js extended JavaScript to the server-side, developers could use the same language they already knew to create backend apps.
Core Concepts of Node.JS:
- Event Loop: Comprehending the event-driven, non-blocking design of Node.js.
- Modules: Using need and module.exports (CommonJS), code can be imported and exported.
- npm (Node Package Manager): Project dependency management with npm (Node Package Manager).
- Asynchronous Programming: Using async/await, callbacks, and promises.
- Operations on the File System: Reading and writing files.
- Making a Simple Web Server: Making use of the included http module.
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Integrating the MEAN Stack
You can create a complete mean stack sample project with the help of this below guide.
Here is the ways to integrate the MEAN stack:
Connecting Angular to the Backend:
- Making HTTP calls from Angular services to the Express.js API
- Utilizing the Angular frontend for data display and response handling.
- Knowing how to set up CORS (Cross-Origin Resource Sharing) in Express.js.
Using Express.js to create RESTful APIs:
- Establishing API endpoints to create, read, update, and remove data.
- Managing the body data and request parameters.
- Sending the proper HTTP replies and status codes.
Linking MongoDB to Express.js:
- Interacting with the database through a MongoDB driver (such as Mongoose or the native MongoDB driver).
- Establishing data models and schemes, particularly with Mongoose.
- Using the driver to implement CRUD operations.
Data Flow: Knowing how data moves from the Angular frontend to the Express.js API, then to the MongoDB database and back again.
Angular State Management (Real-World Application): Managing data across components with a state management solution (such as Angular Signals) or a simple service-based method.
Authentication and Authorization:
- Implementing user registration and login.
- Employing secure authentication methods such as JSON Web Tokens (JWT).
- Putting role-based authorization into practice to manage access to particular resources.
Form Handling and Validation:
- Using Angular to implement forms that gather user input.
- Using Angular to carry out client-side validation.
- Using Express.js for server-side validation.
Full-Stack Error Handling: Applying uniform error management to both the frontend and backend.
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Conclusion
MEAN Stack has transformed web development by providing a more cohesive and effective development experience by extending the strength and familiarity of JavaScript to the server-side. We hope this MEAN Stack Tutorial would help you gain the fundamental understanding. Kickstart your web development journey in our MEAN Stack Training in Chennai.
