web3dart_get_fee_data

A Dart package for retrieving Ethereum fee data with full EIP-1559 support. Provides an API similar to ethers.js getFeeData().

Features

• ✅ EIP-1559 Support: Get maxFeePerGas and maxPriorityFeePerGas for modern transactions
• ✅ Legacy Compatibility: Automatic fallback to gasPrice for older networks
• ✅ Custom Error Handling: Optional onError callback for custom fallback strategies

Installation

Add this package to your pubspec.yaml:

dependencies:
  web3dart_get_fee_data: ^1.1.0

Then run:

dart pub get

Usage

import 'package:web3dart/web3dart.dart';
import 'package:web3dart_get_fee_data/web3dart_get_fee_data.dart';
import 'package:http/http.dart';

void main() async {
  final httpClient = Client();
  final ethClient = Web3Client('https://eth.llamarpc.com', httpClient);

  try {
    final feeData = await getFeeData(ethClient);

    if (feeData.maxFeePerGas != null) {
      print('EIP-1559: ${feeData.maxFeePerGas} wei');
    } else {
      print('Legacy: ${feeData.gasPrice} wei');
    }
  } finally {
    ethClient.dispose();
    httpClient.close();
  }
}

Advanced Usage

Custom Error Handling

Use the onError callback for custom fallback strategies:

final feeData = await getFeeData(
  client,
  onError: (context) {
    print('Error in ${context.operation}: ${context.error}');
    print('Stack trace: ${context.stackTrace}');
    
    // Custom fallback strategies
    if (context.operation == 'eth_maxPriorityFeePerGas') {
      // Use zero priority fee for networks like Arbitrum
      return BigInt.zero;
    }
    
    // Use default fallback
    return context.fallbackValue;
  }
);

API Reference

getFeeData(Web3Client client, {onError})

Parameters:

• client: A connected Web3Client instance
• onError: Optional callback for custom error handling

Returns: Future<FeeData> with current network fees

Example:

Future<FeeData> getFeeData(
  Web3Client client, {
  BigInt? Function(ErrorContext context)? onError,
})

FeeData

Property	Type	Description
gasPrice	BigInt?	Legacy gas price in wei (always provided)
maxFeePerGas	BigInt?	EIP-1559 max fee per gas (when supported)
maxPriorityFeePerGas	BigInt?	EIP-1559 priority fee (when supported)

ErrorContext

Provides comprehensive error information to onError callbacks:

Property	Type	Description
operation	String	The operation that failed (e.g., 'eth_maxPriorityFeePerGas')
error	dynamic	The original error that occurred
stackTrace	StackTrace	Stack trace when the error occurred
fallbackValue	BigInt?	Default fallback value that would be used
gasPrice	BigInt	Current gas price in wei
baseFeePerGas	BigInt?	Current base fee per gas in wei (EIP-1559 networks)

License

MIT License - see LICENSE file.