Pass Value to Closure

Use closure to pass data between two controllers

You can try

class FirstView: UITableViewController {

    @IBOutlet weak var titleLabel: UILabel!

    @IBAction func goToSecond(_ sender: UIButton) {

        self.performSegue(withIdentifier: "segue1", sender: nil)
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

        if segue.identifier == "segue1" {
            let des = segue.destination as! SecondViewController
            des.change = { [weak self] (value) in
                print(value)
                self?.titleLabel.text = "SetValue"// set a value
            }
        }
    }

}
class SecondViewController: UIViewController {

    var change : ((Bool) -> Void)?

    @IBAction func pressChangeButton(_ sender: UIButton) {

        change?(true)
    }

}

How to pass closure as a variable?

Here's what I think you want to achieve:

class SomeView {
    var buttonDidPressed: (() -> Void)? = nil {
       didSet {
          button.pressed = buttonDidPressed
       }
    }
    
    let button = MyButton()
    
    func press() {
        button.press()
    }
}

The reason your code isn't working is because in the SomeView.init, buttonDidPressed is nil - i.e. it's a lack of reference. So:

buttonDidPressed = nil
button.pressed = buttonDidPressed 
// is equivalent to
button.pressed = nil

Assigning a new (or different) reference to buttonDidPressed later doesn't change the button.pressed property.

How to pass a variable by value to an anonymous javascript function?

You need to create a new variable on each pass through the loop, so that it'll get captured in the closures you're creating for the event handlers.

However, merely moving the variable declaration into the loop won't accomplish this, because JavaScript doesn't introduce a new scope for arbitrary blocks.

One easy way to force the introduction of a new scope is to use another anonymous function:

for (var i=0;i<inlineRangeNavUrls.length;i++)
{
  curDiv='#' + inlineRangeNavUrls[i][1];
  if ($(curDiv).length)
  {
    (function(curTab)
    {
      $(curDiv).bind("mouseover", function(){showHideRangeSlidingTabs(curTab, true);} );
      $(curDiv).bind("mouseout", function(){showHideRangeSlidingTabs(curTab, false);} );
    })(inlineRangeNavUrls[i][0]); // pass as argument to anonymous function - this will introduce a new scope
  }
}

As Jason suggests, you can actually clean this up quite a bit using jQuery's built-in hover() function:

for (var i=0;i<inlineRangeNavUrls.length;i++)
{
  (function(curTab) // introduce a new scope
  {
  $('#' + inlineRangeNavUrls[i][1])
    .hover(
      function(){showHideRangeSlidingTabs(curTab, true);},
      function(){showHideRangeSlidingTabs(curTab, false);} 
    );
  // establish per-loop variable by passsing as argument to anonymous function
  })(inlineRangeNavUrls[i][0]); 
}

Passing variable to closure

Your goal is to know how to supply a parameter to a closure. It's achieved with call_user_func_array.

Let's define a method in a class which accepts a closure.

class MyTestClass
{
    public function doWork(callable $callback)
    {
        return call_user_func_array($callback, [$this]);
    }
}

$obj = new MyTestClass();

$obj->doWork(function(MyTestClass $obj) {
    // 
});

Note: didn't test, but I take it that's what you were after?

passing parameter to closure function in javascript

Your MyLibrary.MyModule itself is undefined. This is because you're invoking an anonymous function with no return value to assign to it.

I assume you meant to do this instead:

MyLibrary.MyModule = function initialise(id, options) {
            this.id = id;
            this.c = document.getElementById(id);
            this.ctx = this.c.getContext('2d');

            this.properties = {
                setup: {
                    backgroundColour: options.setup.backgroundColour || 'black'
                },

                scale: {
                    show: options.scale.show || true,
                    colour: options.scale.color || 'white'
                },
            }
            console.log(properties.setup.baseFontSize);
        };

Now you can do:

var inst = new MyLibrary.MyModule('c',options);

...and the 'c' and options will be received as arguments to the constructor.

If your purpose for the immediately invoked function expression was to close around some default value that the constructor could reference, then the IIFE would need to return a function that references that value.

How would I pass data using a closure?

Set class Tray like below

class Tray {
    var cart: Items
    var brandName: String
    init(cart: Items,
         brandName: String) {
        self.cart = cart
        self.brandName = brandName
    }
}

In HomeViewController, under addActionHandler append selected items to cart

cell.addActionHandler = { (option: Int) in
    print("Option selected = \(option)")
    item.selectedOption = option
    tray.append(Tray(cart: item, brandName: "<Brand Name>"))
}

Pass tray[] to CartViewController

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if let vc = segue.destination as? CartViewController {
        vc.items = self.selectedItem
        vc.tray = self.tray
    }
}

In CartViewController, pass items to cartCell

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
     let cell = tableView.dequeueReusableCell(withIdentifier: "CartCell", for: indexPath) as! CartCell
     let cart = tray[indexPath.row]
     cell.configure(withItems: cart.cart)
     return cell
}

how to pass function in parameter using closure in swift 5

You first need to create an extension for UIViewController instead of UIAlertController

Also, set the correct closure argument for the function and then call the function like this.

extension UIViewController {
    
    func action(message: String, firstTitle: String, secondTitle: String, firstAction: (() -> Void)? = nil, secondAction: (() -> Void)? = nil) {
        
        let actionSheet = UIAlertController(title: "", message: message, preferredStyle: .actionSheet)
        
        let eButton = UIAlertAction(title: firstTitle ,
                                    style: .default,
                                    handler: {_ in firstAction?()})
        
        let allEButton = UIAlertAction(title: secondTitle,
                                       style: .default ,
                                       handler: {_ in secondAction?()})
        
        let cancelAction = UIAlertAction(title: "Cancel",
                                         style: .cancel,
                                         handler: nil)
        
        
        [eButton, allEButton, cancelAction].forEach { $0.setValue(UIColor.red, forKey: "titleTextColor")}
        
        
        actionSheet.addAction(eButton)
        actionSheet.addAction(allEButton)
        actionSheet.addAction(cancelAction)
        
        present(actionSheet, animated: true, completion: nil)
    }
}

Usage

private extension viewControllerA {
    func alertBottomSheat()  {
        self.action(message: "Update", firstTitle: "Update only", secondTitle: "Update All", firstAction: saveEvent, secondAction: saveEvent)
    }
    
    @IBAction func deleteEventButtonClicked(_ sender: Any) {
        self.action(message: "delete ", firstTitle: "Delete only", secondTitle: "Delete All ", firstAction: { self.deleteEvent()}, secondAction: { self.deleteEvent(deleteAll: true) })
        
    }
    
    func saveEvent() {
        
    }
    
    func deleteEvent(deleteAll: Bool = false) {
        
    }
}

Note: Fixed coding standard rule and var names.

Pass a value to closure function in PHP

Did you try to use use?

public function handle(UserFollowed $event)
{
    $h = new \Acme\Helpers\functions();
    $email = $h->getUserEmail($event->followed);

    Mail::raw('Hi, welcome user!', function ($message) use ($email) {
        $message->to($email)
            ->subject("New follower :)");
    });

}

Swift: Escaping closure How to pass values to previous ViewController after success

You could add the dictionary to your success closure like this:

func addToCart(vc:UIViewController, param:[String:String], completionHandler:@escaping (_ success:Bool, _ errorC : Error?, _ stock_flag : Bool?, result: [String:Any]?) -> Void)
{ ... }

Afterwards you can just use it in the closure.

CartViewModel().addToCart(vc: self, param:params ) { (isDone, error, stock_flag, result) in 
    // Use result here
}