MEAN Stack Development
UNIT-I: HTML5
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Define Form. How to create Form elements?
Forms in HTML are interactive sections that allow users to input data for submission to a server. Form elements are created using the<form>tag, which acts as a container for various input elements like text fields, checkboxes, radio buttons, and submission buttons. Form attributes such as action, method, and enctype define how data is processed. Creating form elements involves using appropriate input tags with relevant attributes, setting up validation rules, and establishing a logical structure that guides users through the data entry process. -
Define Table. How to create a Table and its elements?
Tables in HTML are structured layouts used to present data in rows and columns. They're created using the<table>tag, with rows defined by<tr>tags and cells by<td>or<th>tags for data and headers respectively. Table elements include caption, thead, tbody, and tfoot for organizing content sections. Attributes like colspan and rowspan allow cells to span multiple columns or rows. Tables can be styled using CSS properties like border, cellpadding, and cellspacing to enhance visual presentation and readability. -
Write an HTML code to display your education details in a tabular format.
Creating a table for education details involves establishing a structured layout with appropriate rows and columns. The table would typically include headers for degree/certificate, institution name, year of completion, and grades/percentages. Each qualification would be represented as a row with corresponding data in each column. The table should use proper HTML5 semantic elements like<thead>and<tbody>to distinguish between header and content sections, with appropriate styling for readability and professional appearance. -
How to insert images and media elements in a web page?
Images and media elements are inserted in web pages using specific HTML5 tags. Images are added using the<img>tag with src attribute pointing to the image file and alt text for accessibility. Videos are embedded using the<video>tag with controls, autoplay, and source options. Audio files use the<audio>tag with similar attributes. HTML5 also supports embedded media like maps or external content through the<iframe>tag. These elements can be customized using attributes for dimensions, playback options, and responsiveness across devices. -
Explain in detail about HTML Security with an example, focusing on HTML Injection and Clickjacking.
HTML security involves protecting websites from various attacks. HTML Injection occurs when untrusted data is inserted into a webpage, potentially allowing attackers to execute malicious scripts. This is prevented by validating and sanitizing user inputs and implementing Content Security Policy. Clickjacking is an attack where users are tricked into clicking disguised elements by overlaying transparent frames over legitimate buttons. Protection methods include using X-Frame-Options headers to prevent site embedding and implementing frame-busting scripts. Both vulnerabilities highlight the importance of validating all input data and implementing proper security headers.
UNIT-II: JavaScript
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Define JavaScript. Explain Identifiers and their types with an example.
JavaScript is a lightweight, interpreted programming language primarily used for enhancing web page interactivity. Identifiers in JavaScript are names given to variables, functions, classes, etc. They must begin with a letter, underscore, or dollar sign, followed by letters, numbers, underscores, or dollar signs. Types of identifiers include keywords (like var, let, const), variable names (userName), function names (calculateTotal), class names (UserProfile), and property names (firstName). JavaScript follows camelCase convention for naming variables and functions, while classes typically use PascalCase. -
Elaborate on primitive and non-primitive data types of JavaScript.
JavaScript has two main categories of data types. Primitive data types are immutable basic values stored directly in memory: strings (text), numbers (integers and decimals), booleans (true/false), undefined (uninitialized values), null (intentional absence of value), BigInt (large integers), and Symbol (unique identifiers). Non-primitive or reference data types are mutable objects that store references to memory locations: Objects (collections of key-value pairs), Arrays (ordered collections), Functions (executable code blocks), Date objects, and RegExp (regular expressions). The key difference is that primitive types are compared by value, while non-primitive types are compared by reference. -
Write a JavaScript code for displaying largest of 3 numbers. Input needs to be taken from user.
To find the largest of three numbers in JavaScript, we would create a solution that involves getting user input through prompt dialogs or form elements, converting the input strings to numbers, comparing the values using conditional statements or Math.max() function, and displaying the result. The solution would need to handle potential errors like non-numeric inputs and ensure proper conversion of input values. The program would employ either nested if-else statements or the more elegant approach of using Math.max() to determine the largest value efficiently. -
Discuss about Creating and Inheriting Classes with an example.
In JavaScript, classes were introduced in ES6 as syntactic sugar over prototype-based inheritance. Classes are created using the class keyword, with a constructor method for initialization and additional methods for behavior. Inheritance is implemented using the extends keyword, allowing child classes to inherit properties and methods from parent classes. The super keyword calls the parent constructor and methods. This enables code reusability and the creation of hierarchical relationships between objects. Class instances are created using the new keyword, and both parent and child class methods can be accessed through the inheritance chain. -
Explain about Browser and Document Object Model with an example.
The Document Object Model (DOM) is a programming interface for web documents, representing HTML as a tree structure of objects that can be manipulated with JavaScript. The Browser Object Model (BOM) represents browser components like window, navigator, history, and location. Together, they allow dynamic webpage manipulation. For example, using document.getElementById() retrieves specific elements, while window.location controls navigation. DOM manipulation includes changing content, attributes, styles, and event handling. The DOM enables interactive web applications by providing methods to add, remove, and modify elements on the page in response to user actions.
UNIT-III: Node.js and Express.js
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Define Node.js. Explain the use of Node.js and its applications with an example.
Node.js is an open-source, cross-platform JavaScript runtime environment that executes JavaScript code outside a web browser. It uses an event-driven, non-blocking I/O model, making it lightweight and efficient for data-intensive real-time applications. Node.js is used for building scalable network applications, APIs, microservices, real-time chat applications, streaming services, and command-line tools. It excels in handling concurrent connections and is ideal for applications requiring persistent connections. Its package ecosystem, npm, provides access to thousands of reusable modules. A simple example would be creating a web server that handles multiple client requests simultaneously without blocking the execution thread. -
What is a web server? Write the steps in creation of a web server in Node.js.
A web server is software that processes requests via HTTP protocol, serving web content to clients like browsers. Creating a web server in Node.js involves several steps: First, import the HTTP module which provides server functionality. Next, create a server instance using http.createServer() method, passing a callback function that handles requests and responses. Define how to process incoming requests based on URL paths and HTTP methods. Set up response headers and content types for proper data interpretation. Finally, bind the server to a network port using the listen() method, specifying the port number and optional hostname. This creates a basic server that can receive HTTP requests and send appropriate responses. -
Define File. Discuss about various File operations in Node.js with an example.
In Node.js, a file is a data storage unit on disk that can be manipulated using the fs (file system) module. File operations in Node.js include reading files (fs.readFile, fs.readFileSync), writing files (fs.writeFile, fs.writeFileSync), appending data (fs.appendFile), checking if files exist (fs.exists), getting file information (fs.stat), creating directories (fs.mkdir), listing directory contents (fs.readdir), renaming files (fs.rename), and deleting files (fs.unlink). These operations can be performed synchronously or asynchronously, with the asynchronous versions being preferred for production to avoid blocking the event loop. Node.js also supports streams for handling large files efficiently. -
How Middleware works? Elaborate on chaining of middleware.
Middleware in Express.js are functions that have access to the request object, response object, and the next middleware function in the application's request-response cycle. They can execute code, modify request and response objects, end the request-response cycle, or call the next middleware. Middleware chaining is the sequential execution of multiple middleware functions through the next() function. When one middleware completes its task, it calls next() to pass control to the subsequent middleware. This creates a pipeline where each function processes the request in order, allowing for modular code organization. Middleware can be application-level, router-level, error-handling, or third-party, each serving different purposes in request processing. -
Explain the CRUD Operations in Express.js with example.
CRUD operations in Express.js refer to Create, Read, Update, and Delete functionalities for managing data. Create operations use HTTP POST requests with router.post() to add new data to a database. Read operations use GET requests with router.get() to retrieve data, either all records or specific ones using route parameters. Update operations use PUT or PATCH requests with router.put() or router.patch() to modify existing records. Delete operations use DELETE requests with router.delete() to remove records. Each operation typically involves receiving client data, performing database operations using models (often with Mongoose for MongoDB), and returning appropriate responses with status codes. These operations form the foundation of RESTful APIs built with Express.js.
UNIT-IV: TypeScript and MongoDB
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What is a namespace? Give its significance. How to create and use namespace in TypeScript?
A namespace in TypeScript is a way to organize code by grouping related functionality under a single name, preventing naming conflicts in large applications. Namespaces are significant for encapsulating code, creating logical boundaries, and controlling variable scope accessibility. To create a namespace, use the "namespace" keyword followed by a name and curly braces containing the code. Inside, declare variables, functions, classes, or interfaces that you want to include. To access elements outside the namespace, they must be exported using the "export" keyword. Namespaces can be split across multiple files using reference tags and can be nested for further organization. While still supported, modules are now preferred over namespaces in modern TypeScript applications. -
Define Generic Functions in TypeScript. Explain their implementation with an example.
Generic functions in TypeScript are functions that work with multiple data types rather than a single type. They allow developers to create reusable, type-safe components that maintain type integrity throughout the codebase. Implemented using type parameters enclosed in angle brackets, generic functions define a relationship between inputs and outputs. For example, a generic function to swap values would preserve the specific types of the arguments while allowing different types to be passed. Generic functions can also have constraints that limit which types can be used as arguments, ensuring that only compatible types with required properties or methods are accepted. This provides flexibility while maintaining type safety. -
What is MongoDB? How to handle JSON files with MongoDB?
MongoDB is a NoSQL, document-oriented database that stores data in flexible, JSON-like BSON (Binary JSON) documents. It's designed for scalability, performance, and high availability. JSON files can be handled in MongoDB by importing them using mongoimport utility, which converts JSON data into BSON documents for database storage. Within application code, JSON data can be parsed into JavaScript objects and then inserted into MongoDB collections using insert operations. MongoDB's query language naturally supports working with nested JSON structures through dot notation for accessing embedded fields. For exporting, mongoexport utility converts BSON documents back to JSON format. MongoDB's native compatibility with JSON makes it ideal for web applications that already use JSON for data transfer. -
Explain MongoDB Structure and Architecture with neat diagram.
MongoDB architecture follows a distributed, scalable design. At its core is the document data model where information is stored in BSON format (binary JSON). The architecture consists of multiple layers: storage engines (WiredTiger being default) that handle data persistence, query execution engine for processing queries efficiently, and networking layer for client communication. MongoDB deployments typically include replica sets for high availability, with primary nodes handling writes and secondary nodes providing redundancy. For horizontal scaling, MongoDB uses sharding to distribute data across multiple servers based on shard keys. The architecture also includes config servers to track cluster metadata and mongos routers to direct client requests to appropriate shards, enabling MongoDB to handle large datasets and high-throughput operations. -
What is Constructor in TypeScript? Explain with an example.
A constructor in TypeScript is a special method within a class that is automatically executed when an object of that class is instantiated. It initializes class properties and prepares the object for use. TypeScript constructors are defined using the "constructor" keyword, can accept parameters for initialization, and support access modifiers (public, private, protected) directly in the parameter list as a shorthand for declaring and initializing class properties. They can call parent class constructors using the "super" keyword in derived classes. Constructors may be overloaded with different parameter signatures and can implement dependency injection patterns. They're essential for object-oriented programming in TypeScript, ensuring objects are properly initialized before use.
UNIT-V: Angular
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Elaborate the procedure for passing data from Container Component to child component and vice versa.
Angular facilitates parent-child component communication through two primary mechanisms. To pass data from container (parent) to child component, the @Input() decorator is used in the child component to receive property values set by the parent in the component tag. For the reverse direction, child components emit events to parents using the @Output() decorator with EventEmitter. The child component raises events with the emit() method, and the parent listens by binding to these events in the template. Additionally, parent components can access child component properties and methods directly using template reference variables or ViewChild decorator. These communication patterns establish a clear data flow, maintaining component encapsulation while allowing necessary interactions. -
Explain in detail about various Structural Directives - ngIf, ngFor, ngSwitch with an example each.
Angular's structural directives modify DOM layout by adding, removing, or manipulating elements. NgIf conditionally renders elements based on a boolean expression; when the condition is false, the element and its descendants are removed entirely from the DOM, not just hidden. NgFor iterates over collections to repeat template elements, using a special syntax with local variables for the current item, index, and other iteration metadata. NgSwitch works like a JavaScript switch statement, rendering different templates based on which condition matches the expression, using ngSwitchCase for individual cases and ngSwitchDefault for when no cases match. These directives are preceded by an asterisk (*) which is syntactic sugar for using <ng-template> with more verbose property bindings. -
Demonstrate various Attribute Directives in angular.js with examples.
Angular attribute directives modify the appearance or behavior of existing elements without changing DOM structure. NgStyle allows dynamic application of multiple CSS styles simultaneously by binding to an object where properties are style names and values are style values. NgClass conditionally applies CSS classes, accepting objects with class names as keys and boolean expressions as values to determine which classes are applied. Both directives respond to changes in their bound expressions, updating styles or classes when data changes. Custom attribute directives can be created using the @Directive decorator, implementing functionality in the directive class, and applying it to elements using a selector. These directives enable dynamic styling and behavior modification without complex DOM manipulation. -
Define Routing? Explain Nested Routes in detail.
Routing in Angular is a mechanism for navigating between different components based on the browser URL, creating a single-page application experience. Nested routes represent a hierarchical structure where child routes exist within parent routes, allowing complex layouts with parent-child component relationships. They're configured by adding a children array to route definitions in the routing module. When a nested route is activated, both the parent and child components are displayed, with the child component rendered in the parent's router-outlet. This enables creating layouts with persistent navigation elements while changing only specific sections of the page. Nested routes can be several levels deep, each maintaining its own parameters, and can be configured with route guards for access control at each level. -
How to create and execute the Angular Application? Illustrate.
Creating an Angular application begins with installing Node.js and Angular CLI. Using the command "ng new app-name", CLI generates a new project with the necessary structure and dependencies. The core components include the app module, component files (HTML, CSS, TypeScript), and routing configuration. After customizing components and services as needed, the application is executed using "ng serve" which compiles the TypeScript code, bundles assets, and launches a development server. The application is accessible through a browser at localhost:4200 by default. For production deployment, "ng build --prod" creates optimized bundles that can be deployed to web servers. This workflow leverages Angular's comprehensive tooling to streamline development from creation to execution.