@eklabdev/blingts4/dist/decorators/class/singleton.js

A comprehensive TypeScript decorators library implementing Stage 2 decorators for TS 4.9+

/**
 * Ensures a class has only one instance
 */
export function Singleton() {
    return function (target) {
        // Symbol to store the instance
        const instanceKey = Symbol();
        // Return a class that extends the original
        return class SingletonClass extends target {
            static instance;
            constructor(...args) {
                // Check if we already have an instance
                if (target[instanceKey]) {
                    return target[instanceKey];
                }
                // Create the instance by calling the parent constructor
                super(...args);
                // Store the instance
                target[instanceKey] = this;
            }
        };
    };
}