Author: kodejunction.com

  • IIFE in JS

    IIFE stands for “Immediately Invoked Function Expression” in JavaScript. It is a design pattern where a function is defined and executed immediately after its creation. This pattern is often used to create a private scope for variables, preventing them from polluting the global scope. Here’s a basic example of an IIFE: In this example, an…

  • Lexical Scoping (or Static Scoping) Vs Dynamic Scoping

    Static (or lexical) scoping and dynamic scoping are two different ways that programming languages determine the scope of a variable. JavaScript uses lexical scoping. Lexical Scoping (Static Scoping): Example in JavaScript: Dynamic Scoping: Example (hypothetical) dynamic scoping behavior: In summary, JavaScript employs lexical scoping, where the scope of a variable is determined by its location…

  • Array.from in Javascript

    The Array.from() method in JavaScript is used to create a new, shallow-copied array from an iterable object or an array-like object. It takes an iterable or array-like object as its first argument and an optional mapping function as its second argument. The mapping function is applied to each element in the iterable or array-like object.…

  • JS: Difference between isNan() and Number.isNan()

    isNaN() and Number.isNaN() are both JavaScript functions, but they behave slightly differently. isNaN() Function: Example Number.isNaN() Method: Example: In summary, while both isNaN() and Number.isNaN() are used to check if a value is NaN, Number.isNaN() is more reliable and is generally recommended for checking NaN values in modern JavaScript code due to its lack of…

  • CSRF – Cross-Site Request Forgery

    Cross-Site Request Forgery (CSRF) is a type of security vulnerability that occurs when a malicious website tricks a user’s browser into making an unwanted request to a different site on which the user is authenticated. This can lead to actions being performed on the target site without the user’s knowledge or consent. How about a…

  • Understanding ER Diagrams

    Entity-Relationship (ER) diagrams are a crucial tool in the field of database design and development. They provide a visual representation of the relationships between entities in a database, allowing for effective communication and comprehension of complex data structures. In this article, we will delve into the world of ER diagrams, exploring their components, benefits, and…

  • Multivalued Dependency

    MVD stands for Multivalued Dependency, which is a concept in database normalization theory. It describes a specific type of dependency between attributes in a relational database. Multivalued dependencies arise when an attribute or set of attributes determines a set of multiple values in another attribute, but not uniquely. In other words, if two attributes, A…

  • Database De-Normalization

    Denormalization is the process of intentionally introducing redundancy into a database design for the purpose of improving performance or simplifying query complexity. In a normalized database, data is organized to minimize redundancy and eliminate anomalies, which ensures data integrity. However, in certain cases, denormalization can be strategically applied to balance performance and maintainability trade-offs. Denormalization…

  • Database Normalization (5NF)

    Fifth Normal Form (5NF), also known as Project-Join Normal Form (PJNF), is a level of database normalization that further refines the structure of a database to eliminate certain types of redundancy and anomalies. It addresses cases where information is redundantly stored across multiple rows due to a combination of candidate keys and overlapping multivalued dependencies.…

  • Database Normalization (4NF)

    Fourth Normal Form (4NF) is a level of database normalization that addresses multi-valued dependencies. It ensures that there are no non-trivial multi-valued dependencies between candidate keys and non-key attributes. To achieve 4NF, a database should already be in BCNF. Let’s explore how to use 4NF normalization with an example: Example: Product Supplier Database Consider a…

  • Database Normalization (BCNF)

    Boyce-Codd Normal Form (BCNF) is a higher level of database normalization that addresses certain anomalies that might still exist in databases normalized up to 3NF. To achieve BCNF, a database should already be in 3NF. BCNF ensures that for every non-trivial functional dependency X -> Y, X must be a superkey. Let’s continue using the…