Chainlink: Estimating the price of a call

import { SubscriptionManager } from '@chainlink/functions-toolkit'
import { ethers } from 'ethers'

async function estimateRequestCost() {
  try {
    const provider = new ethers.providers.JsonRpcProvider('CHAINSTACK_SEPOLIA_RPC')
    const signer = ethers.Wallet.createRandom().connect(provider)

    const subscriptionManager = new SubscriptionManager({
      signer,
      linkTokenAddress: '0x779877A7B0D9E8603169DdbD7836e478b4624789', // Sepolia LINK address
      functionsRouterAddress: '0xb83E47C2bC239B3bf370bc41e1459A34b41238D0', // Sepolia Router address
    })

    await subscriptionManager.initialize()

    const estimatedCostInJuels = await subscriptionManager.estimateFunctionsRequestCost({
      subscriptionId: 4062,
      callbackGasLimit: 300000,
      gasPriceWei: BigInt(20000000000), // 20 gwei
      donId: 'fun-ethereum-sepolia-1'
    })

    const estimatedCostInLink = ethers.utils.formatEther(estimatedCostInJuels.toString())

    console.log(`Estimated cost: ${estimatedCostInLink} LINK`)
  } catch (error) {
    console.error('Error:', error)
  }
}

estimateRequestCost()

% node estimateCost.js
Estimated cost: 14.358219259338930318 LINK