ExpandedPromise.ts

class ExpandedPromise<T> extends Promise<T> {
    resolve: (value: T | PromiseLike<T>) => void;
    reject: (reason?: any) => void;

    status: 'pending' | 'fulfilled' | 'rejected' = 'pending';

    constructor() {
        const callbacks: {
            resolve?: ExpandedPromise<T>['resolve'],
            reject?: ExpandedPromise<T>['reject'],
        } = {};

        super((resolve, reject) => {
            callbacks.resolve = (...args) => {
                if (this.status === 'pending') {
                    this.status = 'fulfilled';
                }
                resolve(...args);
            };
            callbacks.reject = (...args) => {
                if (this.status === 'pending') {
                    this.status = 'rejected';
                }
                reject(...args);
            };
        });

        Object.assign(this, callbacks);
    }

    static get [Symbol.species]() {
        return Promise;
    }
}