How test uint from smartcontract with chai?

Question

In my solidity smartcontract, I have a function to return a uint value :

function getUserBalance(address userAddress, address tokenAddress)
        public
        view
        returns (uint256)
    {
        return _stakingUserBalance[userAddress][tokenAddress].stakedAmount;
    }

 I'm using chai for my test on js file, but it seems result is not a number :

let amountForSpenderBeforeWithdraw = await AlyraStackingInstance.getUserBalance(spender, DaiInstance.address);
... // some code
 let amountForSpenderAfterWithdraw = await AlyraStackingInstance.getUserBalance(spender, DaiInstance.address);   

expect(amountForSpenderBeforeWithdraw).to.be.greaterThan(amountForSpenderAfterWithdraw);

When I launch my test with truffle test, my test return following error :

AssertionError: expected 9 to be a number or a date

When I replace with hard coded value, test is ok. When I write values in console, values are ok. Is it a cast problem ?

Thanks for your help

Answer 1

Self answer :

expect(parseInt(amountForSpenderBeforeWithdraw)).to.be.greaterThan(parseInt(amountForSpenderAfterWithdraw));