Getting address of a new contract in truffle with javascript?

Question

I am trying to use truffle-contract and web3 to create a new instance of a contract and then get the contract address of the contract that I just created.

I have tried the following code with a few similar variations but I get an error of the form "Cannot set property 'contractInstance' of undefined"

I understand it can take a few minutes to create the contract but how do I factor this into the code?

What is the recommended way to do this, or best practice?

  createNewContract(value) {
    return new Promise((resolve, reject) => {
      const contract = require('@truffle/contract');
      const transferContract = contract(tokenAbi);
      transferContract.setProvider(that.web3);
      transferContract.new({from: account}).then(function(instance) {
        this.contractInstance = instance.address;
        return instance.address;
      }).then(function(status) {
        if (status) {
          return resolve({status: true});
        }
      }).catch(function(error) {
        console.log(error);
        return reject('new contract error');
      });
    });
  } 

Thanks

Answer 1

One possible solution could be:

// setting up web3 provider
const Web3 = require('web3')
const web3 = new Web3('ws://localhost:8545')
// import contract artifacts from build folder generated
// as a result of truffle migrate command
const sampleContractArtifact = require('./build/SampleContract')

const ContractInstance = async () => {
  //This method find the network id to retrieve the configuration from truffle-config.js file
  const networkId = await web3.eth.net.getId();
  // Retrieve the Network configuration from truffle-config.js file
  const deployedNetwork = sampleContractArtifact.networks[networkId];
  // Initializing the contract
  const SampleContract = new web3.eth.Contract(
    sampleContractArtifact.abi,
    deployedNetwork.address
  );

  return SampleContract;
};

export default ContractInstance;

The above block of code assumes you are using ganache configured to run at port 8545 in truffle.config.js. However, it will work with any network, you need to update your web3 provider accordingly.

Hope it will help.

Answer 2

I solved this by reducing it to a simply async function

  async createNewContract() {
    const that = this;

    const contract = require('@truffle/contract');
    const transferContract = contract(tokenAbi);
    transferContract.setProvider(that.web3);
    let newContract = await transferContract.new({from: that.account});
    this.contractInstance = newContract.address;
    console.log('the new contract created has an address of'+this.contractInstance);
    return this.contractInstance;
  }