Solidity function returns [object Object]

Question

When I run my solidity function, it's supposed to return a string - but it returns [object Object] I'm calling the function in my frontend and logging the result of the function call.

Here is my solidity function call

function getResult() returns(string) {
  return result;
}

This is what I have on the frontend

async getResult() {
  let contractInstance = await MyContract.at(this.state.contractAddress)
  let result = await contractInstance.getResult()
  console.log(`This is the result ${result}`);
}

Answer 1

This would do:

async getResult() {
  let contractInstance = await MyContract.at(this.state.contractAddress);
  let result = await contractInstance.getResult().call();
  console.log(`This is the result ${result}`);
}

Functions that do not require a transaction to be sent can be called directly.

Answer 2

Javascript returns [object Object] when you log out variables that are objects in templates or string concatenations. If you console.log('This is the result ', result); it will return the object itself, which will contain the string you are looking for.

The object will probably look like

{
    0: 'result'
}

Answer 3

I had the same issue, the problem is this line here:

let result = await contractInstance.getResult()

should be

let result = await contractInstance.getResult().call()

if you want to have a look at the json you can use inspect

import {inspect} from 'util'
console.log(inspect(result))

Answer 4

I have worked with web3JS (NodeJS). you can use this:

const Web3 = require("web3")
const web3 = new Web3("https://rpc-provider.....")

var MyContract = new web3.eth.Contract(abi, address);
MyContract.methods.getResult().call()
.then(console.log);

it will definitly console.log the string you want.

make sure you passed RPC-Provider, ABI & Contract Address.