swift how to add a completion block to a function
Simple Swift 4.0 example:
func method(arg: Bool, completion: (Bool) -> ()) {
print("First line of code executed")
// do stuff here to determine what you want to "send back".
// we are just sending the Boolean value that was sent in "back"
completion(arg)
}
How to use it:
method(arg: true, completion: { (success) -> Void in
print("Second line of code executed")
if success { // this will be equal to whatever value is set in this method call
print("true")
} else {
print("false")
}
})