Implementing the Singleton Design Pattern in JavaScript

The Singleton Design Pattern ensures that a class has only one instance and provides a global point of access to that instance. This pattern is often used when exactly one object is enough for handling operation across the system. The Singleton pattern restricts the instantiation of a class to one object and ensures that the same instance is used.

Where is it Used?

The Singleton pattern is commonly used in scenarios where a single point of control is required, such as:

1. Database Connections: Ensuring only one connection is made to a database.
2. Configuration Settings: Managing application-wide settings or state.
3. Logging: Maintaining a single log file across different parts of an application.
4. Caching: Implementing a global cache that is accessible from anywhere in the application.

Example Code

Here is a simple implementation of the Singleton Design Pattern in JavaScript:

class Cache {
  constructor() {
    if (Cache.instance) {
      return Cache.instance;
    }

    this.cache = {};
    Cache.instance = this;

    return this;
  }

  getData() {
    return this.cache;
  }

  setData(key, value) {
    this.cache[key] = value;
  }
}…