动态估算以太坊交易Gas费用(EIP-1559)，附代码（二）

书接上文，这一篇直接上代码，注意先安装依赖：

npm install web3

使用的node版本: 18

估算的费用包括基础费用和优先费用，其中基础费用可以直接用Web3的函数得到，而优先费用则参考历史区块的数据来估算。代码中的estimateGasFees函数可以自行指定取样的百分位。

完整代码：

import Web3 from "web3";
const rpcUrl = "https://eth.llamarpc.com";
const web3 = new Web3(rpcUrl);

/**
 * 根据Gas费用历史数据来进行估算
 * @param {number} blocks - 取样的历史区块数
 * @param {number[]} percentiles - 不同百分位(默认60%, 75%, 90%)的优先费用平均值
 * @returns {Promise<Object>} - 估算的Gas费用
 */
async function estimateGasFees(blocks = 10, percentiles = [60, 75, 90]) {
  try {
    // 获取当前基础费用
    const pendingBlock = await web3.eth.getBlock("pending");
    const baseFeePerGas = Number(pendingBlock.baseFeePerGas);


    const feeHistory = await web3.eth.getFeeHistory(blocks, "pending", percentiles); // 获取历史费用数据
    const formattedBlocks = formatFeeHistory(feeHistory, blocks, false); // 格式化数据
    const priorityFeeEstimates = {}; // 各百分位的平均优先费用
    
    // 历史优先费用平均值
    for (let i = 0; i < percentiles.length; i++) {
      const percentilePriorityFees = formattedBlocks.map(block => block.priorityFeePerGas[i]);
      const sum = percentilePriorityFees.reduce((acc, val) => acc + val, 0);
      priorityFeeEstimates[percentiles[i]] = Math.round(sum / percentilePriorityFees.length);
    }
    
    // 各百分位的Gas费用上限（基础费用加各百分位的优先费用）
    const maxFeeEstimates = {};
    for (const percentile of percentiles) {
      maxFeeEstimates[percentile] = baseFeePerGas + priorityFeeEstimates[percentile];
    }
    
    return {
      baseFeePerGas,
      priorityFeeEstimates,
      maxFeeEstimates
    };
  } catch (error) {
    console.error("Error estimating gas fees:", error);
    throw error;
  }
}

/**
 * 格式化历史费用数据
 * @param {Object} result - 历史费用数据
 * @param {number} blocksToAnalyze - 取样的区块数
 * @param {boolean} includePending - 是否包括当前区块
 * @returns {Array} - 格式化后的历史费用
 */
function formatFeeHistory(result, blocksToAnalyze, includePending) {
  let blockNum = Number(result.oldestBlock);
  let index = 0;
  const blocks = [];
  const oldestBlockNum = Number(result.oldestBlock);
  
  while (blockNum < oldestBlockNum + blocksToAnalyze) {
    if (index < result.baseFeePerGas.length - 1) {
      blocks.push({
        number: blockNum,
        baseFeePerGas: Number(result.baseFeePerGas[index]),
        gasUsedRatio: result.gasUsedRatio[index],
        priorityFeePerGas: result.reward[index].map(x => Number(x)),
      });
    }
    blockNum += 1;
    index += 1;
  }
  
  if (includePending && result.baseFeePerGas.length > blocksToAnalyze) {
    blocks.push({
      number: "pending",
      baseFeePerGas: Number(result.baseFeePerGas[blocksToAnalyze]),
      gasUsedRatio: NaN,
      priorityFeePerGas: [],
    });
  }
  
  return blocks;
}

async function getGasFeeEstimates() {
  try {
    const estimates = await estimateGasFees();
    
    console.log("===== Gas 费用估算 =====");
    console.log(`基础费用: ${web3.utils.fromWei(estimates.baseFeePerGas.toString(), 'gwei')} Gwei`);
    
    console.log("\n优先费用 (Gwei):");
    for (const [percentile, fee] of Object.entries(estimates.priorityFeeEstimates)) {
      console.log(`${percentile}th percentile: ${web3.utils.fromWei(fee.toString(), 'gwei')} Gwei`);
    }
    
    console.log("\nGas费用上限 (Gwei):");
    for (const [percentile, fee] of Object.entries(estimates.maxFeeEstimates)) {
      console.log(`${percentile}th percentile: ${web3.utils.fromWei(fee.toString(), 'gwei')} Gwei`);
    }
    
    return estimates;
  } catch (error) {
    console.error("Failed to get gas fee estimates:", error);
  }
}

// 执行
getGasFeeEstimates().catch(console.error);

export { estimateGasFees, formatFeeHistory, getGasFeeEstimates };

运行该脚本后效果： 

 

输出三个百分位的估算结果，但最后设定Gas费用上限的策略（激进、保守或者平衡）还需要额外的权衡和微调，不过这就不是这篇文章的讨论内容了。