array in a contract in solidity language stay empty after I modify it

Question

I have wrote a contract in solidity language and test it in remix.ethereum.org and all functionality was working, but when I tried to test it with nodejs and web3 library using ganache there was a scenario not working as it should. I modify an array in my contract then I call a function to return that array but what I get is an empty array, I don't know why and tried to search for similar problem but I didn't found.

contract code

pragma solidity ^0.4.17;

contract web2decentorage {
    address public decentorage;
    address public webUser;
    address[] public storageNodes;
    uint userValue;  //this value in wei
    uint storageNodeValue;
    
    function web2decentorage(uint UV, uint SNV) public {
        userValue = UV;
        storageNodeValue = SNV;
        decentorage = msg.sender;   //decentorage ID that will manage this contract
    }
    
    function getPaidByUser() public payable {
        require(msg.value > userValue);    //here we should put the amount of money the user shoudl pay
        webUser = msg.sender;           //save the user ID
    }
    
    function addStorageNode(address A) public restricted {
        storageNodes.push(A);
    } 
    
    function payStorageNode(address A) public restricted {
        for(uint i=0; i<storageNodes.length; i++){
            if(storageNodes[i] == A){
                storageNodes[i].transfer(storageNodeValue);   //amount of money should be sent to a storage node
            }
        }
    }

    function getStorageNodes() public restricted returns(address[]) {
      return storageNodes;
    }

    function getDecentorage() public restricted view returns(address) {
      return decentorage;
    }

    function getwebUser() public restricted view returns(address) {
      return webUser;
    }
    
    modifier restricted() {
        require(msg.sender == decentorage);
        _;
    }
}

test code

beforeEach(async () => {
    accounts = await web3.eth.getAccounts();
    console.log(accounts);

    //deploy to ganache network the contract
    web2decentorage = await new web3.eth.Contract(JSON.parse(interface))
        .deploy({ data:bytecode , arguments: [499,100]})
        .send({from: accounts[0], gas: '1000000'});
});

describe('web2decentorage', ()=>{

    it('a storage node will be part of this contract and be added as one of the storage nodes that stores the data', async() => {
        await web2decentorage.methods.addStorageNode(accounts[1]).call({
            from: accounts[0]
        });

        const returnVal = await web2decentorage.methods.getStorageNodes().call({
            from: accounts[0]
        });

        console.log(returnVal);

        //assert.equal(accounts[2],storageNodes[0]);
    });

    
});

I add a node then check if the array has the added node I find it empty.

Answer 1

await web2decentorage.methods.addStorageNode(accounts[1]).call({
    from: accounts[0]
});

You need to use the .send() function (not .call()) in order to make a transaction that will produce state changes (in your case, pushing the new item of storageNodes to contract storage).

Call is for read-only actions, so you can safely use for interacting with getStorageNodes() for example.