async function estimateGasPrice(provider: JsonRpcProvider): Promise<BigNumber | void> {
try {
const network = await provider.getNetwork()
if (network.name === 'homestead') {
try {
const response = await fetch('https://www.txprice.com/api')
if (response.ok) {
const { data } = await response.json()
console.log(`gas price estimate for ${network.name}: ${utils.formatUnits(data.fast, 'gwei')}`)
return data.fast
}
} catch (error) {
console.error(`txprice api call failed`, error)
}
}
const block = await provider.getBlockWithTransactions('latest')
const block1 = await provider.getBlockWithTransactions(-1)
const block2 = await provider.getBlockWithTransactions(-2)
const transactions = [...block.transactions, ...block1.transactions, ...block2.transactions]
const filteredTxList = transactions.filter((tx) => tx.gasPrice.gt(0)) // filter out miner stuff
const gasPrices = filteredTxList.map((tx) => tx.gasPrice)
const gasSum = gasPrices.reduce((acc, cur) => acc.add(cur), BigNumber.from(0))
const divisor = gasPrices.length || 1
const average = gasSum.div(divisor).mul(102).div(100) // 2% gas price buffer over average rate
console.log(`gas price estimate for ${network.name}: ${utils.formatUnits(average, 'gwei')}`)
return average || BigNumber.from(1)
} catch (error) {
console.error(`failed gas estimation: ${error}`)
return BigNumber.from(1)
}
}