Exchange Protocol Buffers - Node.js

Node.js/TypeScript implementation of the MEXC exchange Protocol Buffer definitions.

Installation

npm install @frank1957/exchange-pb

Usage

TypeScript

import { mexc } from '@frank1957/exchange-pb';

// Create a book ticker
const bookTicker = new mexc.PublicBookTickerV3Api({
    bidPrice: "50000.00",
    bidQuantity: "1.5",
    askPrice: "50001.00",
    askQuantity: "2.0"
});

console.log(`Bid: ${bookTicker.bidQuantity} @ ${bookTicker.bidPrice}`);
console.log(`Ask: ${bookTicker.askQuantity} @ ${bookTicker.askPrice}`);

// Create a wrapper for push data
const wrapper = new mexc.PushDataV3ApiWrapper({
    channel: "[email protected]",
    symbol: "BTCUSDT",
    symbolId: "BTC_USDT",
    createTime: 1640995200000,
    sendTime: 1640995200001,
    publicBookTicker: bookTicker
});

// Serialize to protobuf binary
const buffer = mexc.PushDataV3ApiWrapper.encode(wrapper).finish();
console.log('Serialized buffer size:', buffer.length, 'bytes');

// Deserialize from protobuf binary
const decoded = mexc.PushDataV3ApiWrapper.decode(buffer);
console.log('Decoded symbol:', decoded.symbol);
console.log('Decoded bid price:', decoded.publicBookTicker?.bidPrice);
console.log('Decoded ask price:', decoded.publicBookTicker?.askPrice);

// Convert to plain object for JSON
const plainObject = mexc.PushDataV3ApiWrapper.toObject(decoded);
console.log('Plain object:', JSON.stringify(plainObject, null, 2));

JavaScript

const { mexc } = require('@frank1957/exchange-pb');

// Create a book ticker
const bookTicker = new mexc.PublicBookTickerV3Api({
    bidPrice: "50000.00",
    bidQuantity: "1.5", 
    askPrice: "50001.00",
    askQuantity: "2.0"
});

console.log(`Bid: ${bookTicker.bidQuantity} @ ${bookTicker.bidPrice}`);

// Serialize to binary
const buffer = mexc.PublicBookTickerV3Api.encode(bookTicker).finish();
console.log('Serialized buffer size:', buffer.length, 'bytes');

// Deserialize from binary
const decoded = mexc.PublicBookTickerV3Api.decode(buffer);
console.log('Decoded bid price:', decoded.bidPrice);
console.log('Decoded ask price:', decoded.askPrice);

// JSON conversion
const json = mexc.PublicBookTickerV3Api.toObject(decoded);
console.log('JSON:', JSON.stringify(json, null, 2));

// Create from plain object
const fromObject = mexc.PublicBookTickerV3Api.fromObject({
    bidPrice: "49999.00",
    bidQuantity: "2.0",
    askPrice: "50000.00", 
    askQuantity: "1.8"
});
console.log('From object:', fromObject.bidPrice);

Development

Prerequisites

• Node.js 18+
• npm or yarn

Building

# Install dependencies
npm install

# Generate protobuf code
npm run generate

# Compile TypeScript
npm run compile

# Build everything
npm run build

# Run tests
npm run test

Project Structure

nodejs/
├── package.json         # NPM package configuration
├── tsconfig.json       # TypeScript configuration  
├── scripts/            # Build scripts
│   └── generate.js     # Protobuf code generation
├── src/                # Generated source code
│   ├── index.ts        # Main entry point
│   ├── proto.js        # Generated protobuf code
│   └── proto.d.ts      # TypeScript definitions
└── lib/                # Compiled output (published)

Features

• Full TypeScript Support: Complete type definitions for all protobuf messages
• Runtime Type Safety: protobufjs provides runtime validation
• JSON Compatibility: Seamless conversion between protobuf and JSON
• Binary Serialization: Efficient protobuf binary encoding/decoding
• Tree-shakable: Import only what you need
• Documentation: Generated code includes JSDoc comments

Generated Types

All protobuf messages are available in the mexc namespace:

• mexc.PublicBookTickerV3Api - Best bid/ask prices and quantities
• mexc.PublicMiniTickerV3Api - Mini ticker with basic price info
• mexc.PrivateOrdersV3Api - Order information
• mexc.PushDataV3ApiWrapper - Wrapper for all push data types
• And more...

API Reference

Creating Messages

// Constructor approach
const ticker = new mexc.PublicBookTickerV3Api({
    bidPrice: "50000.00",
    bidQuantity: "1.5"
});

// From plain object
const ticker2 = mexc.PublicBookTickerV3Api.fromObject({
    bidPrice: "50000.00", 
    bidQuantity: "1.5"
});

Serialization & Deserialization

// Create a message
const ticker = new mexc.PublicBookTickerV3Api({
    bidPrice: "50000.00",
    bidQuantity: "1.5",
    askPrice: "50001.00",
    askQuantity: "2.0"
});

// Serialize to protobuf binary
const buffer = mexc.PublicBookTickerV3Api.encode(ticker).finish();
console.log('Buffer size:', buffer.length, 'bytes');

// Deserialize from protobuf binary
const decoded = mexc.PublicBookTickerV3Api.decode(buffer);
console.log('Decoded bid:', decoded.bidPrice); // "50000.00"
console.log('Decoded ask:', decoded.askPrice); // "50001.00"

// Convert to plain object/JSON
const object = mexc.PublicBookTickerV3Api.toObject(decoded);
const json = JSON.stringify(object);

// Create from JSON/plain object
const fromJson = mexc.PublicBookTickerV3Api.fromObject(JSON.parse(json));

Validation

// Verify message structure
const error = mexc.PublicBookTickerV3Api.verify(ticker);
if (error) {
    console.error('Invalid message:', error);
}

Examples

Complete Serialization/Deserialization Example

import { mexc } from '@frank1957/exchange-pb';

// Simulate receiving binary data from WebSocket/API
function simulateReceiveData(): Uint8Array {
    // Create sample data
    const wrapper = new mexc.PushDataV3ApiWrapper({
        channel: "[email protected]",
        symbol: "BTCUSDT",
        symbolId: "BTC_USDT",
        createTime: Date.now(),
        sendTime: Date.now(),
        publicBookTicker: new mexc.PublicBookTickerV3Api({
            bidPrice: "45000.50",
            bidQuantity: "2.5",
            askPrice: "45001.00",
            askQuantity: "1.8"
        })
    });
    
    return mexc.PushDataV3ApiWrapper.encode(wrapper).finish();
}

// Process received binary data
function processReceivedData(buffer: Uint8Array) {
    try {
        // Deserialize the protobuf data
        const wrapper = mexc.PushDataV3ApiWrapper.decode(buffer);
        
        console.log('Channel:', wrapper.channel);
        console.log('Symbol:', wrapper.symbol);
        
        if (wrapper.publicBookTicker) {
            console.log('Best Bid:', wrapper.publicBookTicker.bidPrice, 
                       '@', wrapper.publicBookTicker.bidQuantity);
            console.log('Best Ask:', wrapper.publicBookTicker.askPrice, 
                       '@', wrapper.publicBookTicker.askQuantity);
        }
        
        // Convert to JSON for storage/logging
        const jsonData = mexc.PushDataV3ApiWrapper.toObject(wrapper);
        console.log('JSON:', JSON.stringify(jsonData, null, 2));
        
    } catch (error) {
        console.error('Failed to decode protobuf data:', error);
    }
}

// Usage
const binaryData = simulateReceiveData();
processReceivedData(binaryData);

See the examples/ directory for more usage examples including:

• Basic message creation and serialization
• Working with complex nested messages
• JSON conversion patterns
• Error handling
• Performance optimization tips