getGasInEIP1559 method

Future<Map<String, EIP1559Information>> getGasInEIP1559({ int historicalBlocks = 10, })

Implementation

Future<Map<String, EIP1559Information>> getGasInEIP1559(
    {int historicalBlocks = 10}) async {
  final List<String> rates = ['slow', 'medium', 'fast'];
  final List<Map<String, dynamic>> history = [];
  final Map<String, EIP1559Information> result = {};

  final Map<String, dynamic> feeHistory = await getFeeHistory(
    historicalBlocks,
    atBlock: const BlockNum.current(),
    rewardPercentiles: [25, 50, 75],
  );

  for (int index = 0; index < historicalBlocks; index++) {
    history.add({
      'blockNumber': feeHistory['oldestBlock'] + BigInt.from(index),
      'baseFeePerGas': feeHistory['baseFeePerGas'][index],
      'gasUsedRatio': feeHistory['gasUsedRatio'][index],
      'priorityFeePerGas': feeHistory['reward'][index],
    });
  }

  final BlockInformation latestBlock = await getBlockInformation(
    blockNumber: const BlockNum.current().toString(),
  );
  final BigInt baseFee = latestBlock.baseFeePerGas!.getInWei;

  for (int index = 0; index < rates.length; index++) {
    final List<BigInt> allPriorityFee = history.map<BigInt>((e) {
      return e['priorityFeePerGas'][index] as BigInt;
    }).toList();
    final BigInt priorityFee = allPriorityFee.max;
    final BigInt estimatedGas = BigInt.from(
      0.9 * baseFee.toDouble() + priorityFee.toDouble(),
    );
    final BigInt maxFee = BigInt.from(1.5 * estimatedGas.toDouble());

    if (priorityFee >= maxFee || priorityFee <= BigInt.zero) {
      throw Exception('Max fee must exceed the priority fee');
    }

    result[rates[index]] = EIP1559Information(
      lastBaseFeePerGas: EtherAmount.inWei(baseFee),
      maxPriorityFeePerGas: EtherAmount.inWei(priorityFee),
      maxFeePerGas: EtherAmount.inWei(maxFee),
      estimatedGas: estimatedGas,
    );
  }

  return result;
}