Truffle: 'func.call()' retrieves the return-value of a non-constant function

Question

I've just learned that one can easily obtain the return-value of a non-constant function, by using myContract.func.call() (instead of myContract.func(), which retrieves a response object).

Up until now, I've always added inside func an event containing the return-value, and then parsed the response object returned from myContract.func() in order to extract that value.

This has also been the guidance in dozens of answers across his website!

Questions:

1. How is it possible that so many people here have missed this?
2. Is it possibly just a tweak added in Truffle, or can one rely on it when writing an operational Web3.js script?

For the record, I am using Truffle v4.1.14, which relies on Web3 v0.20.6.

Here is the contract that I've used for testing this:

pragma solidity 0.4.24;

contract MyContract {
    uint public kkk;
    function func() public returns (uint) {
        kkk += 100;
        return kkk;
    }
}

And here is the actual test:

contract("Test", function(accounts) {
    it("MyContract", async function() {
        const myContract = await artifacts.require("MyContract").new();
        const x = await myContract.func();
        const y = await myContract.func.call();
        console.log(x);
        console.log(y.toFixed());
    });
});

Thank you!

Answer 1

I always use myContract.func.call(). Actuall I have never heard that myContract.func().

After all this is the recommended way of doing it!! Furthermore, the performance is better (I think).

1. Maybe that's your perception? Read the official web3 documentation. I read every page of it. Here is the link to the correct article.
2. I don't use truffle and it works nonetheless. This function is implemented in plain web3.

I hope this information helps.