Language Fundamentals
Core JavaScript language concepts: variables, scopes, types, functions and execution contexts.
What this section covers
This category dives into the basic building blocks of JavaScript: how values are represented, how scope and hoisting work, function types, and execution contexts. These fundamentals are essential to reason about program flow and common bugs.
Why this matters to a developer
Mastering these fundamentals reduces debugging time and prevents common mistakes
like accidental globals, unexpected this values, and confusing scoping issues.
It also makes learning advanced topics easier.
How to use this section
Start with Variables & Scopes to understand how identifiers are resolved, then proceed to Functions and Execution Context.
🔗 Related:
FAQ
Q: Is JavaScript dynamically typed?
A: Yes — types are associated with values rather than variables, so a variable can hold different typed values over time.
Topics in this section
Functions
How functions work in JavaScript, differences between function declarations, expressions, and arrow functions.
Variables and Scopes
How variable declarations (var, let, const) work and scope rules in JavaScript.
Data Types
Primitive and reference data types in JavaScript and how they behave.
Type Coercion
How JavaScript coerces types implicitly and best practices to avoid pitfalls.
Operators
Common operators in JavaScript and how operator precedence and associativity affect expressions.
Execution Context
How functions and code blocks create execution contexts, and the role of the call stack.