Closures and Higher-Order Functions

Closures and Higher-Order Functions

In this lesson — part of Advanced Features — you'll learn closures and higher-order functions in Regular Expressions and why it matters in real work.

Why it matters

Functions that take or return functions unlock concise, composable code.

Key ideas

• Functions as values
• map / filter / reduce
• Callbacks
• Composition

In practice

Here's the idea in pseudocode — the exact syntax varies by language:

// Regular Expressions: map
doubled = nums.map(n => n * 2)

Try it yourself

Exercise: In Regular Expressions, use map and filter to get the squares of the even numbers.

Recap

You now understand closures and higher-order functions and can apply it in Regular Expressions. Mark this lesson complete and continue to the next one.