FeeOracle

import { FeeOracle } from '@voltaire/FeeOracle'

const oracle = FeeOracle({ provider })

// Get current fee data
const feeData = await oracle.getFeeData()
console.log(`Gas price: ${feeData.gasPrice}`)
console.log(`Base fee: ${feeData.baseFeePerGas}`)

// Estimate EIP-1559 fees with priority
const fees = await oracle.estimateEip1559Fees({ priority: 'high' })
const tx = {
  maxFeePerGas: fees.maxFeePerGas,
  maxPriorityFeePerGas: fees.maxPriorityFeePerGas,
}

// Watch for fee updates
const unsubscribe = oracle.watchFees(
  (data) => console.log(`New base fee: ${data.baseFeePerGas}`),
  { pollingInterval: 12000 }
)

function FeeOracle(options: FeeOracleOptions): FeeOracleInstance

const feeData = await oracle.getFeeData()

console.log(`Gas price: ${feeData.gasPrice}`)           // Legacy gas price
console.log(`Base fee: ${feeData.baseFeePerGas}`)       // EIP-1559 base fee
console.log(`Max fee: ${feeData.maxFeePerGas}`)         // Suggested max fee
console.log(`Priority fee: ${feeData.maxPriorityFeePerGas}`) // Suggested priority fee
console.log(`Blob fee: ${feeData.blobBaseFee}`)         // EIP-4844 blob fee
console.log(`Block: ${feeData.blockNumber}`)            // Block this data is from

// Default (medium priority)
const fees = await oracle.estimateEip1559Fees()

// High priority for urgent transactions
const urgentFees = await oracle.estimateEip1559Fees({ priority: 'high' })

// Low priority for non-urgent transactions
const cheapFees = await oracle.estimateEip1559Fees({ priority: 'low' })

// Custom base fee buffer (50% instead of default 25%)
const bufferedFees = await oracle.estimateEip1559Fees({
  priority: 'medium',
  baseFeeMultiplier: 1.5
})

// Basic usage
const unsubscribe = oracle.watchFees((feeData) => {
  console.log(`Base fee: ${feeData.baseFeePerGas}`)
})

// With custom polling interval (every 6 seconds)
const unsubscribe = oracle.watchFees(
  (feeData) => updateUI(feeData),
  { pollingInterval: 6000 }
)

// With AbortSignal for cleanup
const controller = new AbortController()
oracle.watchFees(
  (feeData) => process(feeData),
  { signal: controller.signal }
)

// Later: stop watching
controller.abort()
// or: unsubscribe()

type FeeDataType = {
  /** Current gas price (legacy transactions) */
  readonly gasPrice: bigint
  /** Current base fee per gas (EIP-1559, null if not supported) */
  readonly baseFeePerGas: bigint | null
  /** Suggested max fee per gas (EIP-1559) */
  readonly maxFeePerGas: bigint | null
  /** Suggested max priority fee per gas (EIP-1559) */
  readonly maxPriorityFeePerGas: bigint | null
  /** Current blob base fee (EIP-4844, null if not supported) */
  readonly blobBaseFee: bigint | null
  /** Block number this data was fetched from */
  readonly blockNumber: bigint
}

interface FeeEstimateOptions {
  /** Priority level for fee estimation */
  priority?: 'low' | 'medium' | 'high'
  /** Multiplier for base fee buffer (default: 1.25) */
  baseFeeMultiplier?: number
}

interface FeeOracleOptions {
  /** EIP-1193 provider */
  provider: {
    request(args: { method: string; params?: unknown[] }): Promise<unknown>
  }
  /** Default priority fee percentile (default: 50) */
  priorityFeePercentile?: number
  /** History blocks to analyze for priority fee (default: 4) */
  historyBlocks?: number
}

import { FeeOracle } from '@voltaire/FeeOracle'

const oracle = FeeOracle({ provider })
const fees = await oracle.estimateEip1559Fees({ priority: 'high' })

const tx = {
  to: '0x...',
  value: 1000000000000000000n, // 1 ETH
  maxFeePerGas: fees.maxFeePerGas,
  maxPriorityFeePerGas: fees.maxPriorityFeePerGas,
}

const hash = await wallet.sendTransaction(tx)

import { FeeOracle } from '@voltaire/FeeOracle'

const oracle = FeeOracle({ provider })

// Update UI every block (~12s on mainnet)
oracle.watchFees((feeData) => {
  const gweiBaseFee = Number(feeData.baseFeePerGas) / 1e9
  document.getElementById('baseFee').textContent = `${gweiBaseFee.toFixed(2)} gwei`

  if (feeData.maxPriorityFeePerGas) {
    const gweiPriority = Number(feeData.maxPriorityFeePerGas) / 1e9
    document.getElementById('priorityFee').textContent = `${gweiPriority.toFixed(2)} gwei`
  }
}, { pollingInterval: 12000 })

const oracle = FeeOracle({ provider })
const fees = await oracle.estimateEip1559Fees({ priority: 'medium' })

// On non-EIP-1559 chains, both values equal the adjusted gas price
console.log(fees.maxFeePerGas === fees.maxPriorityFeePerGas) // true

// Analyze more blocks for smoother estimates
const oracle = FeeOracle({
  provider,
  historyBlocks: 10,           // Look at last 10 blocks
  priorityFeePercentile: 75    // Target 75th percentile
})

const feeData = await oracle.getFeeData()