Why Closure expression syntax in Swift? - Purpose & Use Cases

The Big Idea

Discover how a tiny piece of code can save you from writing dozens of extra functions!

The Scenario

Imagine you want to sort a list of names alphabetically. Without closures, you have to write a full function separately and then tell the sorting method to use it.

The Problem

This approach is slow because you write extra code for simple tasks. It's easy to make mistakes by mixing up function names or parameters. It also clutters your code with many small functions that are used only once.

The Solution

Closure expression syntax lets you write small chunks of code right where you need them. You can quickly create a sorting rule without naming a separate function. This keeps your code clean, easy to read, and less error-prone.

Before vs After

✗ Before

func compareNames(a: String, b: String) -> Bool {
    return a < b
}
names.sorted(by: compareNames)

✓ After

names.sorted(by: { (a, b) in a < b })

What It Enables

It enables writing concise, flexible code blocks that can be passed around and used immediately, making your programs simpler and more powerful.

Real Life Example

When building an app, you might want to filter a list of tasks by priority. Using closure expressions, you can quickly write the filtering logic right where you call the filter method, without extra functions.

Key Takeaways

Writing separate functions for simple tasks is slow and cluttered.

Closure expression syntax lets you write quick, inline code blocks.

This makes your code cleaner, easier to read, and less error-prone.