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id title description keywords
xrc20-token-ethers.js
Sending XRC20 Tokens on the XDC Network Using Ethers.js
Use Ethers.js to send XRC20 tokens over XDC network
docs
apothem
token
XRC20
ethers.js

🧭 Table of contents

📰 Overview

Ethers.js is a library written in Javascript which simplifies blockchain interactions.

What you will learn

In this tutorial, you will learn how to import ethers.js, transact an XRC20 token, and set gas prices appropriately.

What you will do

  • Import ethers.js
  • Transfer an XRC20 token
  • Verify Transaction

📰 About XRC20 Tokens

XRC20 is a set of rules to standardize assets on the XinFin network. Every XRC20 Token must be able to execute the following methods:

  • totalSupply()
  • balanceOf(address account)
  • allowance(address owner, address spender)
  • transfer(address recipient, uint amount)
  • approve(address spender, uint amount)
  • transferFrom(address sender, address recipient, uint amount)

These are the minimum required methods that allow an asset on the XinFin network to be called an XRC20 token. Also, a XRC20 token must be able to emit the following Events on the blockchain:

  • Approval(address indexed tokenOwner, address indexed spender, uint tokens)
  • Transfer(address indexed from, address indexed to, uint tokens)

Events are helpers that come in handy in the exhaustive labor of indexing state changes, and they are essential to off-chain applications to find relevant data on the blockchain. By mapping all Transfer events, for example, we can fetch all the historic data on token transfers more easily.

Last but not least, a few contract constants that are public that are also very important to have are:

  • name
  • symbol
  • decimals

Without these public constants, it would be impossible to label tokens on block explorers, for example. In this tutorial we will deploy a XRC20 token that have all the Methods, Events and Constants mentioned above.

🚀 Setting up the development environment

There are a few technical requirements before we start. Please install the following:

⚒ Starting a new NPM Project and Installing Dependencies

Lets start by setting up our folder, we are creating a project called XRC20, create a new XRC20 folder by running on terminal

mkdir XRC20 && cd XRC20

Initialize new project in that folder:

npm init

Tip: to generate project without any questions you can use npm init -y

Install necessary dependencies:

npm install ethers dotenv

💵 Transacting an XRC20 token contract on the XDC Network with ethers

Before sending actual transactions we have to do some preparations.

💵 Add funds to wallet using Apothem Faucet

Go to https://faucet.apothem.network/ and paste your address and press Request 1000 XDC faucet

If you don't have XDC address yet, you can create new wallet using XDCPay

💵 What is an XDC transaction

An XDC transaction is a set of instructions one account sends to another. Transactions can be used to transfer native XDC token or for interactions with smart contracts.

💵 Setting up env file

You can use .env.example as a template.

Your .env file should look like this:

XINFIN_NETWORK_URL=https://erpc.xinfin.network
XINFIN_PRIVATE_KEY=0xyourprivatekey
APOTHEM_NETWORK_URL=https://erpc.apothem.network
APOTHEM_PRIVATE_KEY=0xyourprivatekey
XRC20_TOKEN_ADDRESS=0xyourtokenaddress

Tip: never commit files containing your seed phrase or private key to a git

❕ Keep in mind that you need to replace xdc prefix in your token address with 0x. So token address xdcfc1b5137a6c8dffcf816857463afbb4672d462f3 will became 0xfc1b5137a6c8dffcf816857463afbb4672d462f3.

If you don't have any XRC20 token, you can follow one of those tutorials to create one:

If you don't know what private key is or how to get it, this is how you can copy your private key from XDCPay stage0 stage1 stage2 stage3

💵 Using ethers to transact XRC20

Create a file named send_token.js in your project with following content:

require('dotenv').config()
const ethers = require('ethers')
const XRC20ABI = require('./XRC20.json')

const testnetProvider = new ethers.providers.JsonRpcProvider(process.env.APOTHEM_NETWORK_URL)
const wallet = new ethers.Wallet(process.env.APOTHEM_PRIVATE_KEY, testnetProvider)
const walletSigner = wallet.connect(testnetProvider)

// we are using our address as a recipient, but you can use any address you want
const recipient_address = wallet.address
const your_xrc20_token_address = process.env.XRC20_TOKEN_ADDRESS
const number_of_tokens = ethers.utils.parseUnits('10', 18)

async function main() {
  const contract = new ethers.Contract(
    your_xrc20_token_address,
    XRC20ABI,
    walletSigner
  )

  const receipt = await contract.transfer(recipient_address, number_of_tokens)

  console.log(receipt.hash)
}

main()

Now lets go through each line:

const XRC20ABI = require('./XRC20.json')

In order to interact with the contract, you need to provide an ABI or application binary interface. This is basically just list of functions and events which explains how to interact with smart contract. You can copy ABI from here XRC20 ABI

const testnetProvider = new ethers.providers.JsonRpcProvider(process.env.APOTHEM_NETWORK_URL)

We create an rpc provider to be able to send and receive messages from blockchain.

const wallet = new ethers.Wallet(process.env.APOTHEM_PRIVATE_KEY, testnetProvider)
const walletSigner = wallet.connect(testnetProvider)

This is our wallet which is used to sign transactions. We are connecting it to our rpc provider.

const recipient_address = wallet.address
const your_xrc20_token_address = process.env.XRC20_TOKEN_ADDRESS
const decimals = 18
const number_of_tokens = ethers.utils.parseUnits('10', decimals)

This is some arguments which we will use in our transaction. recipient_address is the recipient we want send tokens to, your_xrc20_token_address is XRC20 token we will transfer, decimals is decimals value for your token and number_of_tokens is amount of tokens we will send.

const recipient_address = "0x585dd46bfa516cc4325d877c614321f22ec7ce5e"
const your_xrc20_token_address = process.env.XRC20_TOKEN_ADDRESS
const decimals = 18
const number_of_tokens = ethers.utils.parseUnits('10', decimals)

If you would like to send the tokens to a different recipient_address simply replacewallet.address with the XDC address you would like to send the tokens to, being sure to replace the "xdc" prefix with "0x".

const contract = new ethers.Contract(
  your_xrc20_token_address,
  XRC20ABI,
  walletSigner
)

We create a contract instance which we use to interact with our XRC20 contract on blockchain. First argument is token address, second is ABI and third is our wallet to sign transaction.

const receipt = await contract.transfer(recipient_address, number_of_tokens)
console.log(receipt.hash)

Now lets run it!

node send_token.js

Then wait few seconds and you should see something like this

0xabf5957a25f943dfb1b71c6d9fc041c7c419b6440af4661f8aab21fc185bd134

🔍 Verifying transaction via Apothem network explorer

After running our script, we received a transaction hash. We can use it to check transaction on a blockchain. To do this, go to https://explorer.apothem.network and paste your transaction hash in search field.

You should see this. txinfo

Here we can see that our transaction ended with success. txstatus

This is how much we ended up paying for our transaction. txprice

And here is how much tokens we sent. tokenamount

For more information about ether.js check out ethers.js github repo and ethers.js documentation website.
For more information about XinFin Network, Please Visit XDC Network Documentation on GitBook.
You can find resources used for this tutorial here example-xrc20-transfer.