JavaScript Tutorial

JavaScript scope refers to the context in which variables, functions, and objects are defined. It determines the accessibility and visibility of these elements within the code. Understanding scope is crucial for writing maintainable and error-free JavaScript code.

JavaScript has three types of scope:

• Block scope
• Function scope
• Global scope

JavaScript collections refer to data structures in the JavaScript programming language that are used to store and manipulate collections of values or objects. These collections provide various ways to organize and access data efficiently. There are several built-in collection types in JavaScript, and developers can also create custom collections as needed.

In JavaScript, collections like arrays, objects, sets, and maps are built-in language features. They are part of the core JavaScript language and do not require any external extensions or libraries to use. JavaScript provides these data structures as fundamental constructs for working with and organizing data within your programs.

Variables are containers for storing data in JavaScript. JavaScript variables can be declared in 4 ways:

• Automatically

• var: Declares a variable with function scope. It's less commonly used in modern JavaScript due to its potential for scope-related issues.

• let: Declares a variable with block scope, limiting it to the block or statement in which it's defined. It allows reassignment.

• const: Declares a constant variable with block scope. Once assigned, its value cannot be changed.

Choosing between them depends on your needs for variable scope and mutability. const is preferred when you don't intend to change the variable's value, while let is suitable for variables that need to be reassigned. var is generally avoided in modern JavaScript due to its quirks related to scope.

We'll discuss the differences in Scope, Redeclaration, and Hoisting.

In JavaScript, an array is a special object that provides a way to store and organize data. It is a linear, ordered collection of elements, and an index can access each element. The array object in JavaScript comes with various built-in methods for manipulating and working with arrays.