JavaScript Control Flow and Collections (Arrays, Objects, Sets, Maps)

This section marks a major transition from simply storing data to controlling the logic and structure of your applications. You will learn how to direct the “flow” of your code through decision-making and automation, while mastering the various ways JavaScript organizes complex data sets. We will explore the vital distinction between how JavaScript handles primitives vs. reference values in memory and harness modern ES6 features to write cleaner, more efficient code. Mastering these structural pillars is what allows you to move beyond simple scripts and start building functional, real-world programs.

Conditional Logic & Scope: Controlling program flow with if/else and switch statements, using the ternary operator for concise logic, and understanding how curly braces {} create boundaries for your variables.

Try/Catch Error Handling: Learning to anticipate and gracefully handle runtime errors using try, catch, and finally blocks to prevent your app from crashing.

Arrays & Basic Methods: Learn how to create arrays (literals), access elements by their index, and perform structural manipulation. This lesson covers fundamental properties and methods for managing array contents and basic searching. Core Methods Include: .length (property) for counting items; .push() / .pop() for adding or removing from the end; .unshift() / .shift() for adding or removing from the beginning; .splice() for adding, removing, or replacing items anywhere in the array; .reverse() for flipping the order of elements; .concat() for merging arrays together; .slice() for creating a copy of a portion of an array; .indexOf() / .includes() for checking the existence and position of items; and .join() for converting an array into a single string.

Loops & Iteration: Automating repetitive tasks with for, while, and do...while loops. Understanding iterables and using the modern for...of loop to iterate over arrays and strings, plus controlling loops with break and continue.

Objects & JSON: Modeling real-world entities with key-value pairs, understanding the strict syntax rules of JSON, and using the global JSON object to convert data between formats.

Primitive vs. Reference Values: A deep dive into memory: learning why primitives are copied by value, while arrays and objects are passed by reference (and how this affects your data).

Sets & Maps: Stepping beyond objects and arrays to use Map for high-performance key-value storage and Set for managing collections of unique values.

Mutable vs. Immutable: Learn how primitive data types are immutable (passed by value), while objects, arrays and functions (which are both types of objects) are mutable (passed by reference). Also learn the difference between creating shallow copies and deep copies of data when working with mutation.