How to get ERC-20 token transfer logs using ethers.js
How to get ERC-20 token transfer logs using ethers.js
This recipe shows you how to use the Ethers library with a Chainstack Ethereum node to retrieve transfer logs for an ERC-20 token.
const ethers = require('ethers');
// Initialize connection to the node.
const nodeUrl = "CHAINSTACK_NODE_URL";
const provider = new ethers.JsonRpcProvider(nodeUrl);
// Import and parse ABI for ERC-20 standard.
const abi = [
// In this case, we only import the 'Transfer' event part of the ABI.
"event Transfer(address indexed from, address indexed to, uint amount)"
];
// Create contract instance using an ERC-20 contract address and ABI.
const address = '0x4d224452801ACEd8B2F0aebE155379bb5D594381' // APE token
const contract = new ethers.Contract(address, abi, provider)
async function getLogs() {
// Edit the range of blocks that you want to get logs from
const range = 100; // Get logs from the past 100 blocks
const latestBlock = await provider.getBlockNumber()
const from = latestBlock - range
// queryFilter takes the name of the event and from and to block as parameters.
const transferEvents = await contract.queryFilter('Transfer', from, latestBlock)
return transferEvents
}
async function main() {
const ape_logs = await getLogs();
//console.log(ape_logs) // Print full logs
// Parse the logs and extract only tx hash, from address, to address, and amount transferred.
for (let object of ape_logs){
console.log(`Transaction hash of APE transfer: ${object.transactionHash}`)
console.log(`From: ${object.args.from}`)
console.log(`To: ${object.args.to}`)
console.log(`Amount of APE transferred: ${ethers.formatEther(String(object.args.amount))} \n`)
}
}
main()
$ node index
Transaction hash of APE transfer: 0x3125accac13704e1bb017021dd385293e79c7bc3b1090fd82df690249116c5d4
From: 0x74de5d4FCbf63E00296fd95d33236B9794016631
To: 0x51C72848c68a965f66FA7a88855F9f7784502a7F
Amount of APE transferred: 782.652322144396771286
You will need a Chainstack account and an Ethereum node to follow this recipe.
- Install node.js in case it is not installed yet.
Create a new directory for your project, then install the ethers.js library.
npm install ethers
Create a new file, index.js, import the ethers.js library, and initialize a new provider instance using your Chainstack node URL.
Paste your Chainstack node URL in the nodeUrl const.
index.js
const ethers = require('ethers');
// Initialize connection to the node.
const nodeUrl = "CHAINSTACK_NODE_URL";
const provider = new ethers.JsonRpcProvider(nodeUrl);
Now we need to create a smart contract instance using the address and ABI.
In this case, we only use the part of the ABI describing the transfer event.
This specific example retrieves the transfer logs for the APE token, but you can use any ERC-20 token smart contract address.
index.js
// Import and parse ABI for ERC-20 standard.
const abi = [
// In this case, we only import the 'Transfer' event part of the ABI.
"event Transfer(address indexed from, address indexed to, uint amount)"
];
// Create contract instance using an ERC-20 contract address and ABI.
const address = '0x4d224452801ACEd8B2F0aebE155379bb5D594381' // APE token
const contract = new ethers.Contract(address, abi, provider)
Create a function called getLogs where we define the range of blocks to query and call the queryFilter function to retrieve the transfer logs.
We query the past 100 blocks in this example and use the getBlockNumber() method to identify the latest block.
index.js
async function getLogs() {
// Edit the range of blocks that you want to get logs from
const range = 100; // Get logs from the past 100 blocks
const latestBlock = await provider.getBlockNumber()
const from = latestBlock - range
// queryFilter takes the name of the event and from and to block as parameters.
const transferEvents = await contract.queryFilter('Transfer', from, latestBlock)
return transferEvents
}
Now we can create a main() function used to run the main program.
This function will call the getLogs() function and parse the response extracting only the data that we want; in this case:
- Transaction hash
- From address
- To address
- Amount of Ape tokens transferred
index.js
async function main() {
const ape_logs = await getLogs();
//console.log(ape_logs) // Print full logs
// Parse the logs and extract only tx hash, from address, to address, and amount transferred.
for (let object of ape_logs){
console.log(`Transaction hash of APE transfer: ${object.transactionHash}`)
console.log(`From: ${object.args.from}`)
console.log(`To: ${object.args.to}`)
console.log(`Amount of APE transferred: ${ethers.formatEther(String(object.args.amount))} \n`)
}
}
main()
Now you can save and run the file with:
node index.js
The script will retrieve the logs from the past 100 blocks and print the transfer information on the screen.
const ethers = require('ethers');
// Initialize connection to the node.
const nodeUrl = "CHAINSTACK_NODE_URL";
const provider = new ethers.JsonRpcProvider(nodeUrl);
// Import and parse ABI for ERC-20 standard.
const abi = [
// In this case, we only import the 'Transfer' event part of the ABI.
"event Transfer(address indexed from, address indexed to, uint amount)"
];
// Create contract instance using an ERC-20 contract address and ABI.
const address = '0x4d224452801ACEd8B2F0aebE155379bb5D594381' // APE token
const contract = new ethers.Contract(address, abi, provider)
async function getLogs() {
// Edit the range of blocks that you want to get logs from
const range = 100; // Get logs from the past 100 blocks
const latestBlock = await provider.getBlockNumber()
const from = latestBlock - range
// queryFilter takes the name of the event and from and to block as parameters.
const transferEvents = await contract.queryFilter('Transfer', from, latestBlock)
return transferEvents
}
async function main() {
const ape_logs = await getLogs();
//console.log(ape_logs) // Print full logs
// Parse the logs and extract only tx hash, from address, to address, and amount transferred.
for (let object of ape_logs){
console.log(`Transaction hash of APE transfer: ${object.transactionHash}`)
console.log(`From: ${object.args.from}`)
console.log(`To: ${object.args.to}`)
console.log(`Amount of APE transferred: ${ethers.formatEther(String(object.args.amount))} \n`)
}
}
main()
$ node index
Transaction hash of APE transfer: 0x3125accac13704e1bb017021dd385293e79c7bc3b1090fd82df690249116c5d4
From: 0x74de5d4FCbf63E00296fd95d33236B9794016631
To: 0x51C72848c68a965f66FA7a88855F9f7784502a7F
Amount of APE transferred: 782.652322144396771286
const ethers = require('ethers');
// Initialize connection to the node.
const nodeUrl = "CHAINSTACK_NODE_URL";
const provider = new ethers.JsonRpcProvider(nodeUrl);
// Import and parse ABI for ERC-20 standard.
const abi = [
// In this case, we only import the 'Transfer' event part of the ABI.
"event Transfer(address indexed from, address indexed to, uint amount)"
];
// Create contract instance using an ERC-20 contract address and ABI.
const address = '0x4d224452801ACEd8B2F0aebE155379bb5D594381' // APE token
const contract = new ethers.Contract(address, abi, provider)
async function getLogs() {
// Edit the range of blocks that you want to get logs from
const range = 100; // Get logs from the past 100 blocks
const latestBlock = await provider.getBlockNumber()
const from = latestBlock - range
// queryFilter takes the name of the event and from and to block as parameters.
const transferEvents = await contract.queryFilter('Transfer', from, latestBlock)
return transferEvents
}
async function main() {
const ape_logs = await getLogs();
//console.log(ape_logs) // Print full logs
// Parse the logs and extract only tx hash, from address, to address, and amount transferred.
for (let object of ape_logs){
console.log(`Transaction hash of APE transfer: ${object.transactionHash}`)
console.log(`From: ${object.args.from}`)
console.log(`To: ${object.args.to}`)
console.log(`Amount of APE transferred: ${ethers.formatEther(String(object.args.amount))} \n`)
}
}
main()
$ node index
Transaction hash of APE transfer: 0x3125accac13704e1bb017021dd385293e79c7bc3b1090fd82df690249116c5d4
From: 0x74de5d4FCbf63E00296fd95d33236B9794016631
To: 0x51C72848c68a965f66FA7a88855F9f7784502a7F
Amount of APE transferred: 782.652322144396771286