Managing Gas Limits

Set transaction gas limits on peaq using ethers.js. Configure a provider and wallet, submit a transfer, and adjust limits based on gas usage.

Setting a gas limit yourself caps what a transaction can cost you. If execution needs more gas than the limit, the transaction runs out of gas and reverts instead of spending more than you expected. Libraries like ethers.js and web3.js both let you set it. This guide uses ethers.js.

Prerequisites

• You understand transactions, gas, and gas pricing on EVM networks.
• You have Node.js and ethers.js installed.
• You have a funded account and the peaq RPC endpoint.
• You keep secrets in environment variables, for example in a .env file.

Instructions

1. Set up the environment

• Install dependencies:

npm install ethers dotenv

• Set ESM module: Add the following to your package.json to allow for ESM modules.

"type": "module",

• Configure environment variables: Create a .env file with the following content:

PRIVATE_KEY=0xYOUR_PRIVATE_KEY
PEAQ_RPC_URL=https://quicknode1.peaq.xyz

List your .env file in .gitignore so it is never checked into version control.

2. Set up the provider and wallet

Create a sendTransaction.js file, load the environment variables, initialize the provider with the peaq RPC endpoint, and load the wallet from the private key.

//sendTransaction.js

import 'dotenv/config';
import { ethers } from 'ethers';

const provider = new ethers.JsonRpcProvider(process.env.PEAQ_RPC_URL);
const wallet = new ethers.Wallet(process.env.PRIVATE_KEY, provider);

3. Decide on a gas limit

Choose a suitable gas limit. Start with a safe upper bound, and adjust later as needed.

const gasLimit = 200000; // adjust to your transaction's complexity

4. Craft the transaction

Include the gasLimit in the transaction object.

const tx = {
    to: '0xRECEIVER_ADDRESS', // replace with the address you want to send to
    value: ethers.parseEther('0.01'), // amount of PEAQ to send
    gasLimit: gasLimit
};

5. Send the transaction

Send the transaction and wait for it to be mined. If it runs out of gas, the try/catch block catches the error.

async function sendTransaction() {
    try {
        const response = await wallet.sendTransaction(tx);
        console.log('Transaction hash:', response.hash);

        const receipt = await response.wait();
        console.log('Transaction confirmed in block:', receipt.blockNumber);
    } catch (error) {
        // Failure could be due to insufficient gasLimit
        console.error('Transaction failed:', error);
    }
}

sendTransaction();

6. Adjust gas limits over time

• If your transactions run out of gas, raise the limit.
• If you consistently use much less gas than the limit, lower it.
• For scripts that send transactions regularly, a predefined gas limit protects you against sudden gas spikes.
• To set the limit from the transaction itself instead of a fixed number, see Estimating Gas Fees.