grammY ctx.api.config.use payload type-check

example.ts

ctx.api.config.use((prev, method, payload) => {
    if (isPayloadOfType(payload, method, 'sendMessage')) {
        // payload is now of type Payload<'sendMessage', R>
        payload.reply_markup = {
            ...payload.reply_markup,
            keyboard: numberKeyboard.build(),
        };
    }

    return prev(method, payload);
});

isPayLoadOfType.ts

const isPayloadOfType = <R extends RawApi, Q extends Methods<R>, M extends Q, T extends Q>(
    payload: Payload<M, R>,
    method: M,
    desired: T,
): payload is Payload<T, R> => {
    // eslint-disable-next-line @typescript-eslint/ban-ts-comment
    // @ts-ignore
    return method === desired;
};

// Usage
if (isPayloadOfType(payload, method, 'sendMessage')) {
    // payload is now of type Payload<'sendMessage', R>
}