mtcute/packages/tl/README.md

@mtcute/tl

TL schema and related utils used for MTCute.

Generated from TL layer 143 (last updated on 18.06.2022).

About

This package contains JSON schema, type declarations, binary (de-)serialization, errors, RSA keys and helper functions.

Package's major version is always TL schema layer number, so version 42.0.0 means that this version was generated from TL layer 42.

• JSON schema, types, binary (de-)serialization and helper functions are generated directly from .tl files that are automatically fetched from TDesktop repository.
• Errors are generated from errors.csv that is automatically fetched from Telethon repository.
• RSA keys info is generated based on manually extracted PEMs from Telegram for Android source code.

Contents

@mtcute/tl

Documentation

TypeScript typings and type helpers generated from the schema.

By default, all types are immutable (have their fields marked as readonly). That is because most of the time you don't really need to modify the objects, and modifying them will only lead to confusion. However, there are still valid use-cases for mutable TL objects, so you can use exported tl.Mutable type to make a given object type mutable.

tl is exported as a namespace to allow better code insights, and to avoid cluttering global namespace and very long import statements.

MTProto schema is available in namespace mtp, also exported by this package.

import { tl } from '@mtcute/tl'
const obj: tl.RawInputPeerChat = { _: 'inputPeerChat', chatId: 42 }
console.log(tl.isAnyInputPeer(obj)) // true

RPC errors are also exposed in this package in tl.errors namespace:

import { tl } from '@mtcute/tl'
try {
    await client.call(...)
} catch (e) {
    if (e instanceof tl.errors.ChatInvalidError) {
        console.log('invalid chat')
    } else throw e
}

@mtcute/tl/api-schema

Documentation

JSON file describing all available TL classes, methods and unions. Can be used to write custom code generators

This very file is used to generate binary serialization and TypeScript typings for @mtcute/tl.

import * as tlSchema from '@mtcute/tl/raw-schema'
console.log(`Current layer: ${tlSchema.apiLayer}`)
// Current layer: 124

@mtcute/tl/binary/reader

Documentation

Contains mapping used to read TL objects from binary streams.

import readerMap from '@mtcute/tl/binary/reader'
import { BinaryReader } from './binary-reader'

const reader = new BinaryReader(Buffer.from([...]))
console.log(readerMap[0x5bb8e511 /* mt_message */].call(reader))
// { _: 'mt_message', ... }

@mtcute/tl/binary/writer

Documentation

Contains mapping used to write TL objects to binary streams.

import writerMap from '@mtcute/tl/binary/writer'
import { BinaryWriter } from './binary-writer'

const writer = new BinaryWriter()
writerMap[0x5bb8e511 /* mt_message */].call(writer, { ... })
console.log(writer.result())
// Buffer <11 e5 b8 5b ...>