Key Component of Singleton Method Design Pattern in JavaScript

2. When to use the Singleton Method Design Pattern in JavaScript?

4. Implementation of Singleton Method Design Pattern in JavaScript

3.1. Private Constructor:

The class should have a private constructor to prevent instantiation of the class from external classes.

Javascript

const Singleton = (function () {
  // Private variable to store the instance
  let instance;

3.2. Private Static Instance:

The class should have a private static instance of itself. This instance is the single instance that the pattern ensures.

Javascript

function Singleton() {
    if (instance) {
      // If an instance already exists, return that instance
      return instance;
    }

    // Initialization code
    // ...

    // Assign `this` to the `instance` variable
    instance = this;
  }

3.3. Public Static Method to Access the Instance:

The class provides a public static method that returns the instance of the class. If an instance does not exist, it creates one; otherwise, it returns the existing instance.

Javascript

Singleton.prototype.getInstance = function () {
    return instance;
  };

3.4. Lazy Initialization:

The instance is created only when it is first requested. This is known as lazy initialization. It helps improve performance by avoiding the unnecessary creation of the instance.

Javascript

Singleton.getInstance = function () {
    if (!instance) {
      // Lazy initialization: create the instance only when needed
      instance = new LazySingleton();
    }
    return instance;
  };

3.5. Prevention of Cloning and Serialization:

To maintain the Singleton property, you may need to override the clone method to throw an exception and ensure that the class is not serializable or provide custom serialization logic.

Javascript

function revive(key, value) {
    if (key === '' && value && value.__isSingleton) {
      return instance;
    }
    return value;
  }

Singleton Method Design Pattern in JavaScript

Singleton Method or Singleton Design Pattern is a part of the Gang of Four design pattern and it is categorized under creational design patterns. It is one of the most simple design patterns in terms of modeling but on the other hand, this is one of the most controversial patterns in terms of complexity of usage.

Important Topics for the Singleton Method Design Pattern in JavaScript

What is Singleton Method Design Pattern in JavaScript?
When to use the Singleton Method Design Pattern in JavaScript?
Key Component of Singleton Method Design Pattern in JavaScript:
Implementation of Singleton Method Design Pattern in JavaScript
Use Case of Singleton Method Design Pattern in JavaScript
Advantage of Singleton Method Design Pattern in JavaScript:
Disadvantage Of Singleton Method Design Pattern in JavaScript

Key Component of Singleton Method Design Pattern in JavaScript

3.1. Private Constructor:

3.2. Private Static Instance:

3.3. Public Static Method to Access the Instance:

3.4. Lazy Initialization:

3.5. Prevention of Cloning and Serialization:

Singleton Method Design Pattern in JavaScript

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