Function returns undefined

Question

I have a very simple function in my Solidity contract, that I'm trying to test its return value with Hardhat.

    function mintNFT(address _recipient) public returns (uint256)
    {
        uint256 tokenId = calculateTokenID();
        return tokenId;
    }

where tokenId has some logic to generate a uint256. I've added a console.log(tokenId) in the Smart Contract which correctly prints out the tokenId, however, when returned and attempted to test, it comes back as undefined

const { expect } = require('chai');

// Import utilities from Test Helpers
const { BN, expectEvent, expectRevert } = require('@openzeppelin/test-helpers');

// Load compiled artifacts
const CONTRACT = artifacts.require('MyContract');

// Start test block
contract('CONTRACT', function ([ owner, other ]) {
  beforeEach(async function () {
    this.contract = await CONTRACT.new();
    await this.contract.initialize();
  });

  it("mintNFT generated a valid token ID", async function () {
    const tokendID = await this.contract.mintNFT();
    expect(tokendID.to.equal(1));
  });

Error:

  1) Contract: DPC
       mintNFT generated a valid token ID:
     TypeError: Cannot read properties of undefined (reading 'equal')
      at Context.<anonymous> (test/DPC_NFT.js:29:24)
      at processTicksAndRejections (node:internal/process/task_queues:96:5)

I've even tried hard-coding the function return to a number, and the test still comes back as undefined. Would greately appreciate your help

Answer 1

you are trying to access to property on tokenID that is wrong try this line :

expect(tokenID).to.equal('value you are expect');