JavaScript Design Patterns — Creational — Singleton

Singleton pattern limits the number of instances of a particular object to just one while providing a global access point to this instance.

Singletons reduce the need for global variables, which avoids the risk of name collisions.

In the example below, we check in the constructor() { … } if an Animal instance exists or if we need to create a new one.

class Animal {
  name;

  constructor() {
      if (typeof Animal.instance === 'object') {
        return Animal.instance;
      }
      Animal.instance = this;
      return this;
    }
}

export default Animal;

You can see that code in action on Stackblitz here: https://stackblitz.com/edit/vitejs-vite-an7es6?file=main.js

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