@sigil/simulation

Transaction simulation against forks. Dry-run transactions to see gas, balance changes, and revert reasons.

Installation

pnpm add @sigil/simulation @sigil/fork

Usage

import { createForkService } from '@sigil/fork'
import { createSimulationService } from '@sigil/simulation'

// Create services
const forkService = createForkService('anvil')
const simulationService = createSimulationService(forkService)

// Create a fork first
await forkService.createFork({
  provider: 'anvil',
  forkUrl: 'https://eth-mainnet.g.alchemy.com/v2/YOUR_KEY',
  chainId: 1,
})

// Simulate a transaction
const result = await simulationService.simulate({
  from: '0x...',
  to: '0x...',
  value: 1000000000000000000n,
  data: '0x...',
})

console.log('Success:', result.success)
console.log('Gas used:', result.gasUsed)
console.log('Balance changes:', result.balanceChanges)

API

createSimulationService(forkService: ForkService): SimulationService

Create a simulation service using an existing fork service.

SimulationService

| Method | Description | |--------|-------------| | simulate(tx) | Simulate a transaction | | estimateGas(tx) | Estimate gas for transaction | | getGasPrice() | Get current gas price | | decodeRevertReason(data) | Decode revert reason |

SimulationResult

| Field | Description | |-------|-------------| | success | Whether transaction succeeded | | hash | Transaction hash | | gasUsed | Gas used | | gasLimit | Gas limit | | effectiveGasPrice | Effective gas price | | totalCost | Total cost in wei | | returnValue | Return value | | revertReason | Revert reason if failed | | balanceChanges | Balance changes | | stateChanges | State changes | | logs | Event logs |

FR-006 Fix

Impersonation cleanup is handled in a finally block to ensure accounts are always un-impersonated even if simulation fails.

License

MIT