Plain JS solution with modified version of TelegramAPI (the one based on webogram), updated with current webogram schema and rewritten to remove dependency on JQuery (I will make code prettier and try pull request to the main repository).

P.S.
This is not the actual size of the app, it is with source code :)

Конкурсное задание выполнено не до конца – регистрация не подержана: возвращается ошибка PHONE_NUMBER_INVALID, процесс не завершается. Скорость работы приложения оказалась немного выше средней. Transferred size: 296KB. Реализация экрана чатов не соответствует дизайну предоставленных макетов.

Из прочих недостатков: 

– Экран входа: нет автоматического выбора страны по префиксу; собственное решение для ‘Keep me signed in’; возможность редактировать номер не поддержана.

– Экран чатов: закрепленные и беззвучные чаты никак не выделены в списке бесед; сообщения в группах отображаются по центру; в каналах остаётся поле ввода; некорректный LS для всех сущностей (last seen recently).

Nice solution, auth work fine, monkey is good, custom telegramapi, pagination and scroll loading messages is also nice

Overall a very nice solution. However, images are not always displayed and very long names of chats are not shortened with ‘…’ at the end. Sometimes avatars and names of people are shifted

authentification not work

auth doesnt work:
Uncaught (in promise) Error: No server found for dc 1

All that needs to work - works fine: auth, animations, chats view. Logout looks really nice. Btw some problem with checkbox in the very beginning and not every message in chats is loaded correctly. Also login button seems to appear only after filling phone number. The other is really nice, especially speed of app. Probably winning solution)

For me everything worked fine, I was authorized immediately. Dialogs and messages are up to date. Not everything is visible in the chats but overall I enjoed it.

Archived chats considered as normal, all messages counted as didn't read, messages sending don't work. Smiles, stickers, and attaches don't work. In menu works only the logout. But everything other works perfectly as in original telegram, so my respect to you, guys. I didn't see any freeze or real bug. It's really amazing solution.

This version looks very nice and pretty :)
But the list of chats shown is somehow not complete, probably some issues with the archive...
And there was a couple of strangely rendered pictures (like checkbox of "keep me signed in"), some lack of avatars and `undefined` instead of the field with info about the call.