How Can I Implement the Singleton Pattern in JavaScript Efficiently?

Clean and Simple Implementation of the Singleton Pattern in JavaScript

The singleton pattern ensures that only a single instance of a class can exist. JavaScript offers several approaches for implementing this pattern efficiently.

Method 1: Simple Object Literal

One straightforward approach is to create an object literal and then assign it to a variable. This allows easy access to methods and properties of the singleton instance.

var myInstance = {
  method1: function () {},
  method2: function () {}
};

Method 2: Closure-based Singleton

For creating private members, you can use the module pattern, which involves using a closure.

var myInstance = (function() {
  var privateVar = '';
  function privateMethod () {}
  return {
    publicMethod1: function () {},
    publicMethod2: function () {}
  };
})();

Method 3: ES5 Object Freeze

To prevent modification of the singleton object, you can freeze it using the Object.freeze method.

Object.freeze(myInstance);

Method 4: ES Modules Singleton

In ES6, you can define a singleton using modules with private state.

// my-singleton.js
const privateState = [];
export default {
  method1() {},
  method2() {}
};

// usage
import myInstance from './my-singleton.js';

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