Objects: Reference Types and the Prototype Chain JavaScript is fundamentally object-oriented. Objects store structured data and executable logic. They form the core architecture of the language. Everything in JavaScript, excluding strict primitive types, is an object. Object Fundamentals and Reference Types An object is a dynamic collection of key-value pairs. Keys define properties or methods. Values represent data or executable functions. Objects are reference types. When a developer assigns an object to a variable, the variable stores a memory address. It does not store a discrete copy of the data. Assigning the same object to a second variable duplicates the memory address, not the object. Mutating the object through the second variable alters the original object. ...

Functions: Execution Contexts and Advanced Scoping Functions encapsulate logic into reusable blocks. They modularize code. They create isolated execution contexts. JavaScript treats functions as first-class objects. They execute operations, return values, and accept parameters. Parameter-Passing Basics and Return Statements Parameters dictate the inputs a function accepts. Arguments are the actual values supplied during invocation. JavaScript passes primitive types by value. A copy of the value enters the function. Modifications inside the function do not affect the original variable in the outer scope. ...