Cannot call function even though it is present in the jsonInteface

Question

I have a simple contract with a simple test-function:

pragma solidity ^0.5.0;

contract TestContract{
  uint public a;
  uint public b;

constructor(uint _a, uint _b) public {
  a = _a;
  b = _b;
}

function TestFunc(uint c, uint d) public view returns(bool success){
  if (c == d){
    return false;
  }
  else{
      return true;
  }
}}

I want to deploy this contract on my local instance of Ganache and call the TestFunc function through a javascript file, using web3js functionality. My javascript file is as follows:

const Web3 = require('web3')
const fs = require('fs');

const options = {
    transactionConfirmationBlocks: 1,
}

const web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:7545"), null, options);

const contract_Abi = [...] //Copied from Truffle's TestContract.json file
bytecode = ... // This is the bytecode (not the deployedBytecode) from the TestContract.json file

const contract = new web3.eth.Contract(contract_Abi);

async function call_TestFunc(){
  accounts = await web3.eth.getAccounts();
  const gas = await contract.deploy({data: bytecode, arguments:[1,1]}).estimateGas();
  const response = await contract.deploy({data:bytecode, arguments: [1,1]}).send({
    from: accounts[0],
    gas: gas + 1
  });
  console.log(response.jsonInterface);
  const txHash = await response.TestFunc.sendTransaction([1,2], {from:accounts[0]});
  console.log(txHash);
}

call_TestFunc();

Now when I run this script, the response.jsonInterface shows the following:

AbiModel {
  abi:
   { methods:
      { a: [Object],
        '0x0dbe671f': [Object],
        'a()': [Object],
        b: [Object],
        '0x4df7e3d0': [Object],
        'b()': [Object],
        contractConstructor: [Object],
        TestFunc: [Object],
        '0x3ff9143f': [Object],

        'TestFunc(uint256,uint256)': [Object] },
     events: {} } }

but when reaching the part where TestFunc is called it gives the following error:

UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'sendTransaction' of undefined

How can I call the TestFunc method properly?

Answer 1

I think you want this:

const txHash = await response.methods.TestFunc([1, 2]).send({from: accounts[0]});

Perhaps you're mixing up web3.js 0.2.x syntax with web3.js 1.0-beta syntax?