If the last parameter to a function is a closure, Swift lets you use special syntax called trailing closure syntax. Rather than pass in your closure as a parameter, you pass it directly after the function inside braces.
To demonstrate this, here’s our travel()
function again. It accepts an action
closure so that it can be run between two print()
calls:
func travel(action: () -> Void) {
print("I'm getting ready to go.")
action()
print("I arrived!")
}
Because its last parameter is a closure, we can call travel()
using trailing closure syntax like this:
travel() {
print("I'm driving in my car")
}
In fact, because there aren’t any other parameters, we can eliminate the parentheses entirely:
travel {
print("I'm driving in my car")
}
Trailing closure syntax is extremely common in Swift, so it’s worth getting used to.
SPONSORED Still waiting on your CI build? Speed it up ~3x with Blaze - change one line, pay less, keep your existing GitHub workflows. First 25 HWS readers to use code HACKING at checkout get 50% off the first year. Try it now for free!
Sponsor Hacking with Swift and reach the world's largest Swift community!
Link copied to your pasteboard.