Substrate Telemetry Client

A TypeScript client library for connecting to Substrate Telemetry backend service. Get real-time information about nodes in Substrate-based networks like Polkadot and Kusama.

Installation

yarn install

Basic Usage

import { TelemetryClient, CHAIN_GENESIS } from 'substrate-telemetry-client';

const client = new TelemetryClient();
await client.connect();
client.subscribe(CHAIN_GENESIS.POLKADOT);

// Event-based updates example:
client.onUpdate((nodes) => {
  console.log('Total nodes:', nodes.length);
});

// Polling-based updates examples:

// 1. Get all nodes
const nodes = client.getNodes();
console.log('Current nodes:', nodes.length);

// 2. Get nodes filtered by node names
const nodeNames = ['Alice', 'Bob', 'Charlie'];
const specificNodes = client.getNodesFiltered(node => nodeNames.includes(node.name));

API Reference

TelemetryClient

Constructor Options

interface TelemetryConfig {
  url?: string;                    // Telemetry WebSocket URL
  autoReconnect?: boolean;         // Auto reconnect on disconnect
  maxReconnectAttempts?: number;   // Max reconnection attempts
}

Methods

• connect(): Promise<void> - Connect to telemetry service
• disconnect(): void - Disconnect from service
• subscribe(chain: GenesisHash): void - Subscribe to chain updates
• onUpdate(handler: (nodes: NodeInfo[]) => void): () => void - Register update handler
• getNodes(): NodeInfo[] - Get all nodes
• getNode(id: number): NodeInfo | undefined - Get specific node
• getNodesFiltered(predicate: (node: NodeInfo) => boolean): NodeInfo[] - Filter nodes
• getNodesSorted(compareFn: (a: NodeInfo, b: NodeInfo) => number): NodeInfo[] - Sort nodes
• getChainStats(): ChainStats | undefined - Get chain statistics

Supported Networks

• Polkadot (CHAIN_GENESIS.POLKADOT)
• Kusama (CHAIN_GENESIS.KUSAMA)
• Other Substrate-based networks (use their genesis hash)

Development

# Install dependencies
yarn install

# Build
yarn build

# Run examples
yarn basic
yarn detailed

You can find example code in:

• examples/basic.ts - Simple connection and node information display
• examples/detailed.ts - Detailed output with node information

Issues

If you find a bug or have a feature request, please create an issue in our GitHub repository.

License

MIT License