the `promisify` utility function converts a callback-style function to a promise-style one. It does this elegantly. Below is a generic TypeScript implementation

promisify.ts

export function toPromise<ReturnType extends any[], ArgTypes extends any[]>(callbackFn: (...args: [...ArgTypes, (err: any, ...data: ReturnType) => void]) => void): (...args: ArgTypes) => Promise<ReturnType> {
    return function (...args: ArgTypes): Promise<ReturnType> {
        return new Promise(function (resolve) {
            callbackFn(...args, (err: any, ...data: ReturnType) => resolve(data));
        });
    };
}