Why is Anonymous Class Instantiation Detrimental in JavaScript?

Anonymous Class Instantiation: A Detrimental Practice

In the realm of JavaScript, the concept of anonymous classes, denoted by the omission of the class name, has emerged with the advent of ES6. While this approach may appear alluring, it belies a profound drawback that renders its usage ill-advised.

The true essence of anonymous classes lies in their immediate instantiation. Consider the following code snippet:

var entity = new class {
    constructor(name) { this.name = name; }
    getName() { return this.name; }
}('Foo');
console.log(entity.getName()); // Foo

This code demonstrates the creation of an anonymous class with a constructor and a method. The new keyword is used to instantly instantiate the class, resulting in an object with the specified properties. However, it is crucial to understand the underlying mechanics and potential pitfalls associated with this approach.

Each evaluation of the anonymous class expression generates a new constructor function and its corresponding prototype object. This poses a significant issue because subsequent objects created using this mechanism will not inherit any benefits from the class or prototype. Moreover, the intent of creating a singleton object is undermined, as the constructor remains accessible and a second instance can be facilmente created using new entity.constructor.

In light of these limitations, it is strongly recommended to eschew the use of anonymous class instantiation. A simple object literal offers a superior alternative in terms of simplicity, readability, and efficiency. Consider the following:

var entity = {
    name: 'Foo',
    getName() { return this.name; }
};
console.log(entity.name); // Foo

While the anonymous class pattern may find acceptance in other programming languages, it functions fundamentally differently in JavaScript and should be avoided to ensure code clarity and performance.

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