Functions
Master reusable blocks of code with functions. Learn about parameters, return values, arrow functions, callbacks, and functional programming concepts. Build modular, maintainable code by breaking down complex problems into smaller functions.
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What You'll Learn
Function declaration and expressions
Parameters and arguments
Return values and return statements
Arrow functions and syntax variations
Callbacks and higher-order functions
Function scope and closures
Frequently Asked Questions
What is the difference between a function declaration and a function expression?
Function declarations are hoisted and can be called before they are defined in the code. Function expressions are not hoisted and must be defined before use. Arrow functions are a type of function expression with shorter syntax.
When should I use arrow functions instead of regular functions?
Arrow functions are great for callbacks and when you want to inherit the surrounding context (this). Use regular functions for methods, constructors, or when you need the function to have its own this binding.
What is a callback function?
A callback is a function passed as an argument to another function, which is then executed inside that function. Callbacks are commonly used for asynchronous operations, event handlers, and array methods like map, filter, and reduce.
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