JavaScript SDK Overview

The @qfc/sdk package provides a complete TypeScript SDK for interacting with the QFC blockchain.

Features

• QfcProvider - JSON-RPC provider with QFC-specific methods
• QfcWallet - Wallet with staking operations
• StakingClient - High-level staking API
• Contract Helpers - ERC-20, ERC-721, ERC-1155 utilities
• Type Safety - Full TypeScript support with strict types
• ethers.js v6 - Built on top of ethers.js for compatibility

Installation

npm install @qfc/sdk

Quick Example

import {
  QfcProvider,
  QfcWallet,
  StakingClient,
  parseQfc,
  formatQfc,
  NETWORKS
} from '@qfc/sdk';

// Connect to testnet
const provider = new QfcProvider(NETWORKS.testnet.rpcUrl);

// Create wallet
const wallet = new QfcWallet(privateKey, provider);

// Check balance
const balance = await provider.getBalance(wallet.address);
console.log('Balance:', formatQfc(balance), 'QFC');

// Send transaction
const tx = await wallet.sendTransaction({
  to: '0x...',
  value: parseQfc('10')
});

// Stake tokens
await wallet.stake(parseQfc('1000'));

// Get validators
const validators = await provider.getValidators();

Module Structure

@qfc/sdk
├── Provider
│   ├── QfcProvider        # JSON-RPC provider
│   └── QfcWebSocketProvider # WebSocket subscriptions
├── Wallet
│   └── QfcWallet          # Wallet with staking
├── Staking
│   └── StakingClient      # Staking queries
├── Contract
│   ├── getERC20           # ERC-20 helper
│   ├── getERC721          # ERC-721 helper
│   ├── getERC1155         # ERC-1155 helper
│   └── getMulticall3      # Batch calls
├── Utils
│   ├── parseQfc / formatQfc   # Unit conversion
│   ├── isValidAddress         # Validation
│   └── shortenAddress         # Formatting
├── Constants
│   ├── NETWORKS           # Network configs
│   ├── CONTRACTS          # Known addresses
│   └── GAS_LIMITS         # Gas presets
└── Types
    └── (TypeScript definitions)

Network Constants

import { NETWORKS, getNetwork } from '@qfc/sdk';

// Access network configs
console.log(NETWORKS.testnet.rpcUrl);    // https://rpc.testnet.qfc.network
console.log(NETWORKS.testnet.chainId);   // 9000
console.log(NETWORKS.testnet.explorerUrl); // https://explorer.testnet.qfc.network

// Get by name
const network = getNetwork('testnet');

Error Handling

import { QfcError, SDK_ERRORS } from '@qfc/sdk';

try {
  await wallet.stake(parseQfc('100'));
} catch (error) {
  if (error instanceof QfcError) {
    console.log('Error code:', error.code);
    console.log('Message:', error.message);

    if (error.code === SDK_ERRORS.STAKE_TOO_LOW) {
      console.log('Stake amount is below minimum');
    }
  }
}

TypeScript Support

The SDK is written in TypeScript and exports all types:

import type {
  Block,
  Transaction,
  TransactionReceipt,
  Validator,
  ValidatorSummary,
  StakeInfo,
  Delegation,
  NetworkConfig,
  EpochInfo,
} from '@qfc/sdk';

Compatibility

The SDK is built on ethers.js v6 and extends its classes:

• QfcProvider extends ethers.JsonRpcProvider
• QfcWallet extends ethers.Wallet
• QfcWebSocketProvider extends ethers.WebSocketProvider

This means you can use all ethers.js methods plus QFC-specific ones.

Next Steps

• Provider - RPC methods and network info
• Wallet - Transaction signing and staking
• Contracts - Contract interactions
• Utilities - Helper functions