This is a category which adds methods on UIViewController to provide a handler at the spot that you programmatically perform a segue. This avoids a mess of if, else if, else statements in prepareForSegue:sender:. In fact, you don't even need to implement the method at all if you don't need do anything before the segues called from actions in your storyboard.

NSNumber *blogPostID = @1;
[self performSegueWithIdentifier:@"BlogPost" handler:^(BlogPostVC *blogPostVC) {
    blogPostVC.blogPostID = blogPostID;

}];

Wish you had some immutability in Javascript? Now you can!

var t = {a: 1, b: 2}.immutable();
console.log(t.a, t.b);
try {
  t.a = 3; // ->  Uncaught Error: a is immutable and cannot be modified.
} catch (e) {
  console.log(e);
}

var t2 = t.copy({a: 3});