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Sometimes it's useful to be able to extend a class with new functions. For example let's suppose that a string should be converted to a camel case string. So we need to tell TypeScript, that String contains a function called toCamelCase, which returns a string. interface String { toCamelCase()...

While running any web application it’s necessary to take loading time into consideration. If your code tries to access any element that is not yet loaded, WebDriver will throw an exception and your script will stop. There are three types of Waits - Implicit Waits Explicit Waits Fluent Waits ...

In Racket, we use recursion very frequently. Here is an example of a function that sums all of the numbers from zero to the parameter, n. (define (sum n) (if (zero? n) 0 (+ n (sum (sub1 n))))) Note that there are many helpful convenience based functions used here, such as ...

Standard properties Depending on the type of the property, there are up to 3 methods for a single property. Let <property> denote the name of a property and <Property> the name of the property with an uppercase first letter. And let T be the type of the property; for primitive wrappers ...

The following example shows the declaration of a property (StringProperty in this case) and demonstrates how to add a ChangeListener to it. import java.text.MessageFormat; import javafx.beans.property.SimpleStringProperty; import javafx.beans.property.StringProperty; import javafx.beans.value.Ch...

This example shows how to use a readonly wrapper property to create a property that cannot be written to. In this case cost and price can be modified, but profit will always be price - cost. import java.text.MessageFormat; import javafx.beans.property.IntegerProperty; import javafx.beans.property...

Overall the easiest way to work with JSON is to have a case class mapping directly to the JSON (same fields name, equivalent types, etc.). case class Person( name: String, age: Int, hobbies: Seq[String], pet: Pet ) case class Pet( name: String, `type`: String ) // these...

Prerequisites Intellij IDEA installed (Community or Ultimate edition) Scala Plugin installed in IntelliJ A standard Play project, created for instance with Activator (activator new [nameoftheproject] play-scala). Opening the project Open IntelliJ IDEA Go to menu File > Open ... > c...

It is very easy to pass information between threads using the MVar a type and its accompanying functions in Control.Concurrent: newEmptyMVar :: IO (MVar a) -- creates a new MVar a newMVar :: a -> IO (MVar a) -- creates a new MVar with the given value takeMVar :: MVar a -> IO a -- retrieve...

Debugging is a very powerful way to have a closer look and fix incorrectly working (or non working) code. Run code step by step First thing you need to do during debugging is to stop the code at specific locations and then run it line by line to see whether that happens what's expected. Breakp...

In VBA, Strings can be declared with a specific length; they are automatically padded or truncated to maintain that length as declared. Public Sub TwoTypesOfStrings() Dim FixedLengthString As String * 5 ' declares a string of 5 characters Dim NormalString As String Debug.Print Fi...

The JavaScript coding convention is to place the starting bracket of blocks on the same line of their declaration: if (...) { } function (a, b, ...) { } Instead of in the next line: if (...) { } function (a, b, ...) { } This has been adopted to avoid semicolon insertion ...

The practice of replacing an object with a test double that verifies expectations, for instance asserting that a method has been called, is referred to as mocking. Lets assume we have SomeService to test. class SomeService { private $repository; public function __construct(Repository $r...

Since arrays are reference types, it is possible to have multiple variables pointing to the same array object. Dim array1() As Integer = {1, 2, 3} Dim array2() As Integer = array1 array1(0) = 4 Console.WriteLine(String.Join(", ", array2)) ' Writes "4, 2, 3"

A form gives the user a way to change data in your application, in a structured way. To mutate a simple array of data, we create a form using a form builder: use Symfony\Component\Form\Extension\Core\Type\TextType; use Symfony\Component\Form\Extension\Core\Type\NumberType; use Symfony\Component\F...

manifest.json { "name": "Hello Page", "description": "Add 'Hello' to the current page.", "version": "1.0", "permissions": [ "activeTab" ], "background": { "scripts": [&quo...

AppBundle/Entity/Person.php <?php namespace AppBundle\Entity; /** * Person */ class Person { /** * @var int */ private $id; /** * @var string */ private $name; /** * @var int */ private $age; /** ...

AppBundle/Entity/Person.php <?php namespace AppBundle\Entity; use DoctrineORM\Mapping as ORM; use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity; /** * @ORM\Entity * @ORM\Table(name="persons") * @ORM\Entity(repositoryClass="AppBundle\Entity\PersonRe...

It is possible to define a data type with field labels. data Person = Person { age :: Int, name :: String } This definition differs from a normal record definition as it also defines *record accessors which can be used to access parts of a data type. In this example, two record accessors are de...

One of the most common obstacles using classes is finding the proper approach to handle private states. There are 4 common solutions for handling private states: Using Symbols Symbols are new primitive type introduced on in ES2015, as defined at MDN A symbol is a unique and immutable data typ...