Variables & Data Types
Learn how to store and manipulate data using variables. Understand different data types like strings, numbers, booleans, and more. Master the fundamentals of variable declaration, assignment, scope, and type conversion.
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What You'll Learn
Variable declaration and initialization
Different data types (strings, numbers, booleans, null, undefined)
Variable scope (global, local, block)
Constants and immutability
Type conversion and coercion
Naming conventions and best practices
Frequently Asked Questions
What is the difference between var, let, and const in JavaScript?
var is function-scoped and can be redeclared, let is block-scoped and cannot be redeclared, and const is block-scoped and cannot be reassigned. Modern JavaScript prefers let and const for better scoping and fewer bugs.
How do I choose the right data type for my variable?
Consider what kind of data you need to store: numbers for calculations, strings for text, booleans for true/false conditions, arrays for lists, and objects for complex data structures. Choose the type that best represents your data and its intended use.
What is variable scope and why does it matter?
Scope determines where a variable can be accessed in your code. Variables declared inside a function or block are only accessible within that context. Understanding scope helps prevent naming conflicts and makes code more maintainable.
Ready to Master Variables & Data Types?
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