Functions as First-Class Citizens

Differentiate between function declarations, function expressions, and arrow functions, noting their impact on `this` and hoisting.

Use higher-order functions like map, filter, and reduce to process data collections.

Implement function composition to create a reusable pipeline of operations.

Implement partial application and currying to create specialized functions from more general ones.

Apply rest and spread operators with function arguments and array literals.

Use default parameters and destructuring in function signatures for cleaner interfaces.

Implement callbacks to handle results in both synchronous and asynchronous scenarios.

Write an IIFE (Immediately Invoked Function Expression) and explain its use cases for scope encapsulation.