Hardfork.isPostMerge

import { Hardfork } from 'tevm'

function getConsensusInfo(fork: BrandedHardfork) {
  if (fork.isPostMerge()) {
    return {
      consensus: "Proof of Stake",
      blockProducer: "validator",
      blockReward: "0 ETH (tips only)",
      difficultyOpcode: "PREVRANDAO",
      blockTime: "12s (fixed)"
    }
  }

  return {
    consensus: "Proof of Work",
    blockProducer: "miner",
    blockReward: "2 ETH + fees",
    difficultyOpcode: "DIFFICULTY",
    blockTime: "~13s (variable)"
  }
}

import { Hardfork } from 'tevm'

function validateMiningConfig(fork: BrandedHardfork, config: MiningConfig) {
  if (fork.isPostMerge() && config.mining) {
    throw new Error(
      "Mining not supported after Merge. " +
      "Ethereum uses Proof of Stake consensus."
    )
  }
}

import { Hardfork } from 'tevm'

function handleDifficultyOpcode(fork: BrandedHardfork, value: bigint) {
  if (fork.isPostMerge()) {
    console.log("PREVRANDAO (beacon randomness):", value)
  } else {
    console.log("DIFFICULTY (mining difficulty):", value)
  }
}

import { Hardfork } from 'tevm'

function validateBlock(fork: BrandedHardfork, block: Block) {
  if (fork.isPostMerge()) {
    // PoS validation
    if (block.difficulty !== 0n) {
      throw new Error("PoS blocks must have difficulty = 0")
    }
    if (block.nonce !== 0n) {
      throw new Error("PoS blocks must have nonce = 0")
    }
    if (!block.mixHash) {
      throw new Error("PoS blocks require mixHash (PREVRANDAO)")
    }
  } else {
    // PoW validation
    if (block.difficulty === 0n) {
      throw new Error("PoW blocks must have non-zero difficulty")
    }
  }
}

import { Hardfork } from 'tevm'

function getNetworkType(fork: BrandedHardfork): string {
  return fork.isPostMerge() ? "mainnet-pos" : "mainnet-pow"
}

// Before Merge (PoW)
uint256 randomSeed = block.difficulty;  // Mining difficulty

// After Merge (PoS)
uint256 randomSeed = block.prevrandao;  // Beacon randomness
// Note: block.difficulty still works but returns prevrandao