What is a factory function JavaScript?

In object-oriented programming (OOP), a factory is an object for creating other objects – formally a factory is a function or method that returns objects of a varying prototype or class from some method call, which is assumed to be “new”.

A constructor returns an instance of the class you call it on. A factory function can return anything. You would use a factory function when you need to return arbitrary values or when a class has a large setup process.

2. The main difference between modules and factory functions are simpler than you think. Modules are just files with blocks of code that you can import/export. Whereas factory functions are functions that create objects and return them.

Factories are much more flexible than either constructor functions or classes, and they don’t lead people down the wrong path by tempting them with the `extends` keyword and deep inheritance hierarchies. There are many safer code reuse mechanisms you should favor over class inheritance, including functions and modules.

The factory design pattern says that define an interface ( A java interface or an abstract class) and let the subclasses decide which object to instantiate. The factory method in the interface lets a class defer the instantiation to one or more concrete subclasses.

Factory Method Pattern. A Factory Pattern or Factory Method Pattern says that just define an interface or abstract class for creating an object but let the subclasses decide which class to instantiate. In other words, subclasses are responsible to create the instance of the class.

Factory method is a creational design pattern which solves the problem of creating product objects without specifying their concrete classes. Factory Method defines a method, which should be used for creating objects instead of direct constructor call ( new operator).

Factory function is the most powerful approach for creating the controls dynamically by using model data in UI5. Instead of hard coding the control in view we can dynamically generate the ui5 controls in controller according to data we got from the backend system.

A JavaScript object literal is a comma-separated list of name-value pairs wrapped in curly braces. Object literals encapsulate data, enclosing it in a tidy package. This minimizes the use of global variables which can cause problems when combining code.

The factory function pattern is similar to constructors, but instead of using new to create an object, factory functions simply set up and return the new object when you call the function. Check out this example: const personFactory = (name, age) => { const sayHello = () => console.

While differences may seem trivial, factories are more robust against bugs due to avoiding the this keyword. You should use them in almost all cases. Classes are slightly faster to instantiate, but we’re talking a fraction of a fraction of a millisecond.

A factory constructor is a constructor that can be used when you don’t necessarily want a constructor to create a new instance of your class. This might be useful if you hold instances of your class in memory and don’t want to create a new one each time (or if the operation of creating an instance is costly).

There is technically no class, they’re both just functions. Any function can be invoked as a constructor with the keyword new and the prototype property of that function is used for the object to inherit methods from. “Class” is only used conceptually to describe the above practice.

The factory pattern is a type of Object Oriented pattern which follows the DRY methodology. As the name suggests, object instances are created by using a factory to make the required object for us. … Dynamic object creation: It can be used in cases where the type of the object is decided at runtime.

Factory design pattern is used to create objects or Class in Java and it provides loose coupling and high cohesion. Factory pattern encapsulate object creation logic which makes it easy to change it later when you change how object gets created or you can even introduce new object with just change in one class.

An ObjectFactory is responsible for creating objects of a specific type. … An object factory must implement the ObjectFactory interface. In addition, the factory class must be public and must have a public constructor that accepts no parameters.

1. A class cannot anticipate the type of objects it needs to create beforehand.
2. A class requires its subclasses to specify the objects it creates.
3. You want to localize the logic to instantiate a complex object.

Factory: Client just need a class and does not care about which concrete implementation it is getting. Factory Method: Client doesn’t know what concrete classes it will be required to create at runtime, but just wants to get a class that will do the job.

Example. The Factory Method defines an interface for creating objects, but lets subclasses decide which classes to instantiate. Injection molding presses demonstrate this pattern. Manufacturers of plastic toys process plastic molding powder, and inject the plastic into molds of the desired shapes.

1. Implementation. …
2. Create an interface. …
3. Create concrete classes implementing the same interface. …
4. Create a Factory to generate object of concrete class based on given information. …
5. Use the Factory to get object of concrete class by passing an information such as type. …
6. Verify the output.

The factory method is used to offer a single interface to instantiate one of the multiple classes. In the Factory pattern, the objective is to make the object in such a way that it does not expose to the creation logic to the Client and can always refer to a newly created object with the help of a common interface.

• Abstract Factory Pattern isolates the client code from concrete (implementation) classes.
• It eases the exchanging of object families.
• It promotes consistency among objects.

Aggregation binding requires the definition of a template, which is cloned for each bound entry of the list. For each clone that is created, the binding context is set to the respective list entry, so that all bindings of the template are resolved relative to the entry.

Nearly everything in JavaScript is an object other than six things that are not objects which are — null , undefined , strings, numbers, boolean, and symbols. These are called primitive values or primitive types.

JavaScript has a number of predefined objects. In addition, you can create your own objects. You can create an object using an object initializer. Alternatively, you can first create a constructor function and then instantiate an object invoking that function in conjunction with the new operator.

Spread operator allows an iterable to expand in places where 0+ arguments are expected. It is mostly used in the variable array where there is more than 1 values are expected. It allows us the privilege to obtain a list of parameters from an array.

A factory method is a static method of a class that returns an object of that class’ type. But unlike a constructor, the actual object it returns might be an instance of a subclass. Another advantage of a factory method is that it can return existing instances multiple times.

Classes serve as templates to create new objects. The most important thing to remember: Classes are just normal JavaScript functions and could be completely replicated without using the class syntax. It is special syntactic sugar added in ES6 to make it easier to declare and inherit complex objects.

In JavaScript, there are no classes in the class-based OOP sense of the word. JavaScript works with objects. If you want to encapsulate a few functions and properties together, you would create an object containing functions and properties, and not a class.

JavaScript follows a similar model, but does not have a class definition separate from the constructor. Instead, you define a constructor function to create objects with a particular initial set of properties and values. … The class syntax does not introduce a new object-oriented inheritance model to JavaScript.

A software factory is a structured collection of related software assets that aids in producing computer software applications or software components according to specific, externally defined end-user requirements through an assembly process. … Software factories are generally involved with outsourced software creation.

A class is called an object factory because objects are created from the class that contains common attributes and behaviour. The class behaves like a specification for creating such similar objects.

A JavaScript class is a type of function. Classes are declared with the class keyword. We will use function expression syntax to initialize a function and class expression syntax to initialize a class.

Function declaration is a prototype that specifies the function name, return types and parameters without the function body. Function Definition, on the other hand, refers to the actual function that specifies the function name, return types and parameters with the function body.

Declaration of a variable in a computer programming language is a statement used to specify the variable name and its data type. Declaration tells the compiler about the existence of an entity in the program and its location. … Initialization is the process of assigning a value to the Variable.