javascript · intermediate
JavaScript Deep Dive
Go beyond the basics: master how JavaScript really works under the hood, from coercion and closures to classes, modules, and modern 2026 syntax.
A practical, misconception-busting tour of core JavaScript: values and types, scope and closures, functional array methods, objects, classes, modules, error handling, and the newest syntax you will see in real 2026 codebases. Every lesson ends with a runnable coding challenge.
Values, Scope & Functions
Core mental models: how values behave, how scope works, closures, and functions as first-class values.
- Values, Types, and CoercionLevel 2 · Beginner · Pass the quick check and the coding challenge to continue14m
- Scope and ClosuresFinish the lesson, Pass the quick check and pass the coding challenge in "Values, Types, and Coercion" to unlock this lesson.15m
- Functions as Values and CallbacksFinish the lesson, Pass the quick check and pass the coding challenge in "Scope and Closures" to unlock this lesson.14m
Working with Data
Transform and shape data with array methods, objects, destructuring, spread/rest, and classes.
- Transforming Arrays: map, filter, reduceFinish the lesson, Pass the quick check and pass the coding challenge in "Functions as Values and Callbacks" to unlock this lesson.16m
- Objects and DestructuringFinish the lesson, Pass the quick check and pass the coding challenge in "Transforming Arrays: map, filter, reduce" to unlock this lesson.15m
- Spread, Rest, and ImmutabilityFinish the lesson, Pass the quick check and pass the coding challenge in "Objects and Destructuring" to unlock this lesson.15m
- `this` and Arrow FunctionsFinish the lesson, Pass the quick check and pass the coding challenge in "Functions as Values and Callbacks" to unlock this lesson.14m
- Classes and PrototypesFinish the lesson, Pass the quick check and pass the coding challenge in "`this` and Arrow Functions" to unlock this lesson.15m
- Data Transformation ToolkitComplete "Classes and Prototypes" to unlock this project.~4h
Structuring & Modern JavaScript
Organize code with modules, handle errors properly, and use the syntax that modern 2026 JS codebases rely on.
- Modules: import and exportFinish the project "Data Transformation Toolkit" to unlock this lesson.13m
- Handling Errors: try/catch and Custom ErrorsFinish the project "Data Transformation Toolkit" to unlock this lesson.13m
- Modern Syntax: Optional Chaining, Nullish Coalescing, Template LiteralsFinish the project "Data Transformation Toolkit" to unlock this lesson.12m