completer.ts

export class Completer<T = unknown, E = unknown> {
    private _promise: Promise<T>;
    private _resolve!: (value: T | PromiseLike<T>) => void;
    private _reject!: (reason?: E) => void;

    constructor() {
        this._promise = new Promise<T>((resolve, reject) => {
            this._resolve = resolve;
            this._reject = reject;
        });
    }

    public resolve(value: T): void {
        this._resolve(value);
    }

    public reject(reason: E): void {
        this._reject(reason);
    }

    public promise(): Promise<T> {
        return this._promise;
    }

    public reset() {
        this._promise = new Promise<T>((resolve, reject) => {
            this._resolve = resolve;
            this._reject = reject;
        });
    }
}

// Example usage with default types (T and E as unknown)
const completer1 = new Completer();

// Example usage with a specific type for value and error
const completer2 = new Completer<number, string>();

completer1.promise().then(
    (value) => console.log("Resolved with unknown value:", value),
    (error) => console.log("Rejected with unknown error:", error)
);

completer2.promise().then(
    (value) => console.log("Resolved with number value:", value),
    (error) => console.log("Rejected with string error:", error)
);

// Resolve and reject examples
setTimeout(() => {
    completer1.resolve("A string value"); // Completer1 resolves with a string (unknown type)
}, 1000);

setTimeout(() => {
    completer2.resolve(42);  // Completer2 resolves with a number
}, 2000);

setTimeout(() => {
    completer2.reject("An error occurred");  // Completer2 rejects with a string
}, 3000);