Замена функции в объекте с полной поддержкой типов

replace.ts

// https://stackoverflow.com/questions/49752151/typescript-keyof-returning-specific-type
type KeyOfType<T, V> = keyof {
    [P in keyof T as T[P] extends V ? P : never]: any;
};
type InferArgs<TValueType> = TValueType extends (...args: infer U) => any ? U : never;
type InferReturn<TValueType> = TValueType extends (...args: any) => infer U ? U : never;
const replaceFunction = <
    TArgs extends InferArgs<TObject[TKey]>,
    TReturn extends InferReturn<TObject[TKey]>,
    TCallable extends (...args: any) => any,
    TObject extends Record<string, any>,
    TKey extends KeyOfType<TObject, TCallable>,
>(
    target: TObject,
    name: TKey,
    callback: (oldFunction: TObject[TKey], ...args: TArgs) => TReturn,
) => {
    const oldCallable = target[name];
    const newCallable = (...args: TArgs) => callback(oldCallable, ...args);
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    target[name] = newCallable as any;
};
  
// Пример использования
// Перехватываем функцию GET в роутере Express чтобы знать о регистрации нового маршрута
const router = express.Router();
replaceFunction(router, 'get', (prev, path, ...args) => {
    console.log('Registered new route: ', path);
    return prev.call(router, path, ...args);
});