#!/usr/bin/env npx ts-node
/**
* Gas Tracker - Basic Example
*
* This example demonstrates how to:
* - Monitor gas prices across multiple EVM networks
* - Display current gas prices (slow, standard, fast)
* - Compare gas costs between networks
* - Estimate transaction costs
*
* Difficulty: ⭐ Beginner
* Prerequisites: Node.js 18+, pnpm
* Estimated Time: 10 minutes
*
* @author Nich
* @license MIT
*/
import "dotenv/config"
import Table from "cli-table3"
import chalk from "chalk"
import {
createMCPClient,
callTool,
printHeader,
printSection,
printKeyValue,
printSuccess,
printError,
printInfo,
printWarning,
formatNumber,
formatUSD,
getEnv,
sleep,
NETWORKS
} from "../lib/utils.js"
import type { Client } from "@modelcontextprotocol/sdk/client/index.js"
// ============================================================================
// Configuration
// ============================================================================
// Networks to monitor
const MONITORED_NETWORKS = ["ethereum", "bsc", "arbitrum", "polygon", "base", "optimism"]
// Standard gas units for different transaction types
const GAS_UNITS = {
transfer: 21000,
erc20Transfer: 65000,
swap: 150000,
nftMint: 200000,
contractDeploy: 500000
}
// Refresh interval for continuous monitoring (in seconds)
const REFRESH_INTERVAL = 30
// ============================================================================
// Types
// ============================================================================
interface GasPriceResult {
network: string
chainId: number
gasPrice: {
slow: string
standard: string
fast: string
}
baseFee?: string
priorityFee?: {
slow: string
standard: string
fast: string
}
estimatedCosts?: {
transfer: string
erc20Transfer: string
swap: string
}
lastUpdated: string
}
interface NetworkGasData {
network: string
nativeToken: string
slow: number
standard: number
fast: number
baseFee?: number
transferCost: number
swapCost: number
}
// ============================================================================
// Main Functions
// ============================================================================
/**
* Get gas prices for a specific network
*/
async function getGasPrice(client: Client, network: string): Promise<GasPriceResult | null> {
try {
const result = await callTool<GasPriceResult>(client, "get_gas_price", {
network
})
return result
} catch (error) {
printWarning(`Could not fetch gas for ${network}: ${(error as Error).message}`)
return null
}
}
/**
* Calculate transaction cost in native token
*/
function calculateCost(gasPrice: number, gasUnits: number): number {
// gasPrice is in Gwei, convert to native token
return (gasPrice * gasUnits) / 1e9
}
/**
* Format gas price with color based on value
*/
function formatGasWithColor(gwei: number, network: string): string {
// Define thresholds based on network
const thresholds: Record<string, { low: number; high: number }> = {
ethereum: { low: 20, high: 50 },
bsc: { low: 3, high: 10 },
arbitrum: { low: 0.1, high: 0.5 },
polygon: { low: 50, high: 200 },
base: { low: 0.01, high: 0.1 },
optimism: { low: 0.01, high: 0.1 }
}
const threshold = thresholds[network] || { low: 10, high: 50 }
const formatted = `${formatNumber(gwei, 2)} Gwei`
if (gwei <= threshold.low) {
return chalk.green(formatted)
} else if (gwei >= threshold.high) {
return chalk.red(formatted)
} else {
return chalk.yellow(formatted)
}
}
/**
* Display gas prices in a formatted table
*/
function displayGasTable(gasData: NetworkGasData[]): void {
const table = new Table({
head: [
chalk.bold("Network"),
chalk.bold("🐌 Slow"),
chalk.bold("🚗 Standard"),
chalk.bold("🚀 Fast"),
chalk.bold("Transfer Cost"),
chalk.bold("Swap Cost")
],
style: {
head: [],
border: []
}
})
for (const data of gasData) {
table.push([
`${data.network} (${data.nativeToken})`,
formatGasWithColor(data.slow, data.network.toLowerCase()),
formatGasWithColor(data.standard, data.network.toLowerCase()),
formatGasWithColor(data.fast, data.network.toLowerCase()),
`${formatNumber(data.transferCost, 6)} ${data.nativeToken}`,
`${formatNumber(data.swapCost, 6)} ${data.nativeToken}`
])
}
console.log(table.toString())
}
/**
* Display gas cost comparison for different transaction types
*/
function displayCostComparison(gasData: NetworkGasData[]): void {
printSection("💰 Transaction Cost Comparison (Standard Gas)")
const costTable = new Table({
head: [
chalk.bold("Network"),
chalk.bold("ETH Transfer"),
chalk.bold("ERC20 Transfer"),
chalk.bold("DEX Swap"),
chalk.bold("NFT Mint")
],
style: {
head: [],
border: []
}
})
for (const data of gasData) {
const standard = data.standard
costTable.push([
data.network,
`${formatNumber(calculateCost(standard, GAS_UNITS.transfer), 6)} ${data.nativeToken}`,
`${formatNumber(calculateCost(standard, GAS_UNITS.erc20Transfer), 6)} ${data.nativeToken}`,
`${formatNumber(calculateCost(standard, GAS_UNITS.swap), 6)} ${data.nativeToken}`,
`${formatNumber(calculateCost(standard, GAS_UNITS.nftMint), 6)} ${data.nativeToken}`
])
}
console.log(costTable.toString())
}
/**
* Find the cheapest network for a transaction
*/
function findCheapestNetwork(gasData: NetworkGasData[], txType: keyof typeof GAS_UNITS): NetworkGasData | null {
if (gasData.length === 0) return null
return gasData.reduce((cheapest, current) => {
const cheapestCost = calculateCost(cheapest.standard, GAS_UNITS[txType])
const currentCost = calculateCost(current.standard, GAS_UNITS[txType])
return currentCost < cheapestCost ? current : cheapest
})
}
// ============================================================================
// Main Entry Point
// ============================================================================
async function main(): Promise<void> {
// Get configuration
const continuous = getEnv("CONTINUOUS", "false") === "true"
const networksEnv = getEnv("NETWORKS", "")
const networks = networksEnv
? networksEnv.split(",").map(n => n.trim().toLowerCase())
: MONITORED_NETWORKS
printHeader("⛽ Multi-Chain Gas Tracker")
printInfo(`Monitoring ${networks.length} networks: ${networks.join(", ")}`)
if (continuous) {
printInfo(`Refresh interval: ${REFRESH_INTERVAL} seconds`)
printInfo("Press Ctrl+C to stop")
}
let client: Client | null = null
try {
// Connect to MCP server
printInfo("Connecting to MCP server...")
client = await createMCPClient()
printSuccess("Connected to Universal Crypto MCP")
do {
console.clear()
printHeader("⛽ Multi-Chain Gas Tracker")
printInfo(`Last updated: ${new Date().toLocaleTimeString()}`)
// Fetch gas prices from all networks
printSection("📊 Current Gas Prices")
const gasDataPromises = networks.map(async (network) => {
const result = await getGasPrice(client!, network)
if (!result) return null
const networkConfig = NETWORKS[network]
return {
network: networkConfig?.name || network,
nativeToken: networkConfig?.nativeToken || "ETH",
slow: parseFloat(result.gasPrice.slow),
standard: parseFloat(result.gasPrice.standard),
fast: parseFloat(result.gasPrice.fast),
baseFee: result.baseFee ? parseFloat(result.baseFee) : undefined,
transferCost: calculateCost(parseFloat(result.gasPrice.standard), GAS_UNITS.transfer),
swapCost: calculateCost(parseFloat(result.gasPrice.standard), GAS_UNITS.swap)
} as NetworkGasData
})
const gasResults = await Promise.all(gasDataPromises)
const gasData = gasResults.filter((d): d is NetworkGasData => d !== null)
if (gasData.length === 0) {
printError("Could not fetch gas prices from any network")
} else {
// Display main gas table
displayGasTable(gasData)
// Display cost comparison
displayCostComparison(gasData)
// Show recommendations
printSection("💡 Recommendations")
const cheapestForSwap = findCheapestNetwork(gasData, "swap")
if (cheapestForSwap) {
printSuccess(`Cheapest for swaps: ${cheapestForSwap.network}`)
}
const cheapestForTransfer = findCheapestNetwork(gasData, "transfer")
if (cheapestForTransfer) {
printSuccess(`Cheapest for transfers: ${cheapestForTransfer.network}`)
}
// Gas saving tips
printSection("📝 Gas Saving Tips")
console.log(" • Use Layer 2s (Arbitrum, Base, Optimism) for lower fees")
console.log(" • Time transactions during low activity periods")
console.log(" • Batch multiple operations when possible")
console.log(" • Set appropriate gas limits to avoid overpaying")
}
if (continuous) {
printInfo(`\nRefreshing in ${REFRESH_INTERVAL} seconds...`)
await sleep(REFRESH_INTERVAL * 1000)
}
} while (continuous)
} catch (error) {
printError(`Error: ${(error as Error).message}`)
process.exit(1)
} finally {
if (client) {
await client.close()
}
}
}
// Run if executed directly
main().catch(console.error)
// ============================================================================
// Usage Examples
// ============================================================================
/**
* @example Basic gas check
* ```bash
* npx ts-node basic/gas-tracker.ts
* ```
*
* @example Continuous monitoring
* ```bash
* CONTINUOUS=true npx ts-node basic/gas-tracker.ts
* ```
*
* @example Monitor specific networks only
* ```bash
* NETWORKS=ethereum,arbitrum,base npx ts-node basic/gas-tracker.ts
* ```
*/
