Example code redeeming BPros without Truffle

In the following example we will learn how to:

  • Get the maximum amount of BPro available to redeem.

  • Get BPro balance of an account.

  • Redeem BPros.

We will use the testnet network.

First we create a new node project.

mkdir example-redeem-bpro
cd example-redeem-bpro
npm init

Let's add the necessary dependencies to run the project.

npm install --save web3
npm install --save truffle-hdwallet-provider
const HDWalletProvider = require('truffle-hdwallet-provider');
const Web3 = require('web3');
//You must compile the smart contracts or use the official ABIs of the repository
const MocAbi = require('../../build/contracts/MoC.json');
const MoCInrateAbi = require('../../build/contracts/MoCInrate.json');
const MoCStateAbi = require('../../build/contracts/MoCState.json');
const BProTokenAbi = require('../../build/contracts/BProToken.json');

//Config params to TestNet
const endpoint = 'https://public-node.testnet.rsk.co';
//a mnemonic is 12 words instead of a single private key to sign the //transactions
const mnemonic = 'chase chair crew elbow uncle awful cover asset cradle pet loud puzzle';
const provider = new HDWalletProvider(mnemonic, endpoint);
const web3 = new Web3(provider);

//Contract addresses on testnet
const mocContractAddress = '<contract-address>';
const mocInrateAddress = '<contract-address>';
const mocStateAddress = '<contract-address>';
const bproTokenAddress = '<contract-address>';
const gasPrice = 60000000;

const execute = async () => {
  web3.eth.defaultGas = 2000000;

   * Loads an specified contract
   * @param {ContractABI} abi
   * @param {String} contractAddress
  const getContract = async (abi, contractAddress) => new web3.eth.Contract(abi, contractAddress);

  // Loading moc contract
  const moc = await getContract(MocAbi.abi, mocContractAddress);
  if (!moc) {
    throw Error('Can not find MoC contract.');

  // Loading mocInrate contract. It is necessary to compute commissions
  const mocInrate = await getContract(MoCInrateAbi.abi, mocInrateAddress);
  if (!mocInrate) {
    throw Error('Can not find MoC Inrate contract.');

  // Loading mocState contract. It is necessary to compute absolute max BPRO
  const mocState = await getContract(MoCStateAbi.abi, mocStateAddress);
  if (!mocState) {
    throw Error('Can not find MoCState contract.');

  // Loading BProToken contract. It is necessary to compute user balance
  const bproToken = await getContract(BProTokenAbi.abi, bproTokenAddress);

  const [from] = await web3.eth.getAccounts();

  const redeemBpro = async (bproAmount, vendorAccount) => {
    const weiAmount = web3.utils.toWei(bproAmount, 'ether');

    console.log(`Calling redeem Bpro with account: ${from} and amount: ${weiAmount}.`);
      .redeemBProVendors(weiAmount, vendorAccount)
      .send({ from, gasPrice }, function(error, transactionHash) {
        if (error) console.log(error);
        if (transactionHash) console.log('txHash: '.concat(transactionHash));
      .on('transactionHash', function(hash) {
        console.log('TxHash: '.concat(hash));
      .on('receipt', function(receipt) {
      .on('error', console.error);

  const getAbsoluteMaxBpro = await mocState.methods.absoluteMaxBPro().call();
  const userAmount = await bproToken.methods.balanceOf(from).call();
  const bproFinalAmount = Math.min(userAmount, getAbsoluteMaxBpro);
  console.log('=== User BPRO balance: ', userAmount);
  console.log('=== Max amount of BPro to redeem ', bproFinalAmount);

  const bproAmount = '0.00001';
  const vendorAccount = '<vendor-address>';

  // Call redeem
  await redeemBpro(bproAmount, vendorAccount);

  .then(() => console.log('Completed'))
  .catch(err => {
    console.log('Error', err);

Last updated