How to return value from a Closure in Swift?

You need to return from an @escaping closure.Change the function

func getImageURL(celebrity: String) -> String {}

to

func getImageURL(celebrity: String, completion: @escaping(String)->()) {      // your code      completion(imgURL)}

You can use it as given below

getImageURL(celebrity: String) { (imgURL) in      self.imgURL = imgURL // Using self as the closure is running in background}

Here is an example how I write multiple methods with closures for completion.

class ServiceManager: NSObject {//  Static Instance variable for Singletonstatic var sharedSessionManager = ServiceManager()//  Function to execute GET request and pass data from escaping closurefunc executeGetRequest(with urlString: String, completion: @escaping (Data?) -> ()) {    let url = URL.init(string: urlString)    let urlRequest = URLRequest(url: url!)    URLSession.shared.dataTask(with: urlRequest) { (data, response, error) in        //  Log errors (if any)        if error != nil {            print(error.debugDescription)        } else {            //  Passing the data from closure to the calling method            completion(data)        }    }.resume()  // Starting the dataTask}//  Function to perform a task - Calls executeGetRequest(with urlString:) and receives data from the closure.func downloadMovies(from urlString: String, completion: @escaping ([Movie]) -> ()) {    //  Calling executeGetRequest(with:)    executeGetRequest(with: urlString) { (data) in  // Data received from closure        do {            //  JSON parsing            let responseDict = try JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? [String: Any]            if let results = responseDict!["results"] as? [[String:Any]] {                var movies = [Movie]()                for obj in results {                    let movie = Movie(movieDict: obj)                    movies.append(movie)                }                //  Passing parsed JSON data from closure to the calling method.                completion(movies)            }        } catch {            print("ERROR: could not retrieve response")        }    }  }}

Below is the example how I use it to pass values.

ServiceManager.sharedSessionManager.downloadMovies(from: urlBase) { (movies : [Movie]) in   // Object received from closure      self.movies = movies      DispatchQueue.main.async {            //  Updating UI on main queue            self.movieCollectionView.reloadData()      }}

I hope this helps anybody looking for the same solution.

You are correct, sendTwitterRequest will return after your function has already returned, so there is no way for the outer function to return an imageURL.

Instead, in the closure, take the return value that you want in the cell and store it somewhere (in a member variable) and have the tableView update it itself (e.g. with tableView.reloadData()).

This will cause it to get the cell again (cellForRow ...). Change the implementation to use the member variable where you stored the value from the call.