DON'T DO THIS. Block the thread to resolve a promise synchronously

depromise.ts

const depromise = <T>(promise: Promise<T>): T => {
    let result: T | undefined;
    let error: Error | undefined;
    let isPromisePending = true;

    promise
        .then((res) => {
            result = res;
            isPromisePending = false;
        })
        .catch((err) => {
            error = err;
            isPromisePending = false;
        });

    while (isPromisePending) {
        // This loop blocks the thread, which is NOT recommended.
    }

    if (error) {
        throw error;
    } else {
        if (!result) {
            throw new Error();
        }
        return result;
    }
};

const depromiseCallback = <T>(
    callback: (...params: any[]) => Promise<T>,
): ((...params: any[]) => T) => {
    return function (...params: any[]): T {
        return depromise(callback(...params));
    };
};