[SOLVED] Identifier error

Hey guys
Might be a newbie error but I’m struggling to truffle migrate and I’m getting this error. I didn’t think anything was wrong with my Identifier but i might be wrong.

Screenshot SPDX License

License should be added as comments.

// SPDX-License-Identifier: MIT
1 Like

Hi John
Thank you I’ve just changed that and now my 2 imports for openzeppelin are saying file import callback not supported. I’ve written them exactly how the video has. :slight_smile:

If you have installed contract with npm install --save @openzeppelin/contracts, then maybe check if the node modules folder path is correct.

1 Like

Ok I’ll try that.
Thank you :slight_smile:

If you got the package installed as @johnversus mentioned you can also import it this way

import "@openzeppelin/contracts/utils/Counters.sol";
import "@openzeppelin/contracts/token/ERC721/ERC721.sol";

Hi guys
Thank you for your help I’ve been able to fix the issue.
Cheers

Hey guys
another newbie question lol. I cant figure out how to get rid of this error? everything I’ve tried makes it worse.
Cheers
Screenshot tokenContract not defined

HTML

<!DOCTYPE html>

<html lang="en">

<head>

    <link rel="shortcut icon" href="">

    <meta charset="UTF-8">

    <meta http-equiv="X-UA-Compatible" content="IE=edge">

    <meta name="viewport" content="width=device-width, initial-scale=1.0">

    <title>Morarables</title>

    <link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-0evHe/X+R7YkIZDRvuzKMRqM+OrBnVFBL6DOitfPri4tjfHxaWutUpFmBp4vmVor" crossorigin="anonymous">

    <link rel="stylesheet" href="main.css">

</head>

<body class="bg-dark">

    <nav class="navbar navbar-expand-lg navbar-dark bg-transparent border-bottom border-light>

        <div class="container-fluid">

          <a class="navbar-brand" href="#">Morarable</a>

          <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">

            <span class="navbar-toggler-icon"></span>

          </button>

          <div class="collapse navbar-collapse" id="navbarNav">

            <ul class="navbar-nav mr-auto">

              <li class="nav-item">

                <a class="nav-link active" aria-current="page" href="#">Home</a>

              </li>

            </ul>

          </div>

        </div>

      </nav>

    <div>

        <button id="btnConnect">Connect Wallet</button>

        <button id="btnUserInfo">Profile</button>

        <button id="btnOpenCreateItem">Create</button>

    </div>

    <div id="userInfo">

        <h4>User Profile</h4>

        <input type="text" id="txtUsername" required placeholder="Enter username">

        <input type="text" id="txtEmail" placeholder="Enter email">

        <small>Optional</small>

        <img width="50" height="50" src="" id="imgAvatar" alt="">

        <label for="fileAvatar">Select Avatar</label>

        <input type="file" id="fileAvatar">

        <button id="btnLogOut">Log out</button>

        <button id="btnCloseUserInfo">Close</button>

        <button id="btnSaveUserInfo">Save</button>

    </div>

    <div id="createItem">

        <h4>Create Item</h4>

        <input type="text" id="txtCreateItemName" required placeholder="Enter name">

        <textarea id="txtCreateItemDescription" cols="30" rows="5" placeholder="Enter description"></textarea>

        <input type="number" min="1" step="1" id="numCreateItemPrice" placeholder="Enter price" required>

   

        <label for="selectCreateItemStatus">Status</label>

        <select id="selectCreateItemStatus">        

            <option value="0">Not for sale</option>

            <option value="1">Instant buy</option>

            <option value="2">Accept Offers</option>

        </select>

        <label for="fileCreateItemFile">Select File</label>

        <input type="file" id="fileCreateItemFile">

        <button id="btnCloseCreateItem">Close</button>

        <button id="btnCreateItem">Create!</button>

    </div>

    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/web3.min.js"></script>

    <script src="https://unpkg.com/moralis/dist/moralis.js"></script>

    <script src="main.js"></script>

    <script src="abi.js"></script>

    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.bundle.min.js" integrity="sha384-pprn3073KE6tl6bjs2QrFaJGz5/SUsLqktiwsUTF55Jfv3qYSDhgCecCxMW52nD2" crossorigin="anonymous"></script>

</body>

</html>

Javascript

const serverUrl = "https://5platkya43gg.usemoralis.com:2053/server";

const appId = "iyhSgWOnDLaSy73cTGRPT2pQ1yG6TNbwr5pzKsIo";

const TOKEN_CONTRACT_ADDRESS = "0x9731268F2f3d39eeaF9925F1D8327c26b0Cd0dA2";

Moralis.start({ serverUrl, appId });

init = async () => {

    hideElement(userInfo);

    hideElement(createItemForm);

    await Moralis.enableWeb3();

    window.tokenContract = new web3.eth.Contract(tokenContractAbi, TOKEN_CONTRACT_ADDRESS);

        initUser();

}

initUser = async () => {

    if (await Moralis.User.current()){

        hideElement(userConnectButton);

        showElement(userProfileButton);

        showElement(openCreateItemButton);

    }else{

        showElement(userConnectButton);

        hideElement(userProfileButton);

        hideElement(openCreateItemButton);

        hideElement(createItemForm);

    }

}

login = async () => {

    try {

        await Moralis.authenticate();

        initUser();

    } catch (error) {

        alert(error)

    }

}

logout = async () => {

    await Moralis.User.logOut();

    hideElement(userInfo);

    initUser();

}

openUserInfo = async () => {

    user = await Moralis.User.current();

    if (user){    

        const email = user.get('email');

        if(email){

            userEmailField.value = email;

        }else{

            userEmailField.value = "";

        }

        userNameField.value = user.get('username');

        const userAvatar = user.get('avatar');

        if(userAvatar){

            userAvatarImg.src = userAvatar.url();

            showElement(userAvatarImg);

        }else{

            hideElement(userAvatarImg);

        }

        showElement(userInfo);

    }else{

        login();

    }

}

saveUserInfo = async () => {

    user.set('email', userEmailField.value);

    user.set('username', userNameField.value);

    if (userAvatarFile.files.length > 0) {

        const avatar = new Moralis.File("avatar1.jpg", userAvatarFile.files[0]);

        user.set('avatar', avatar);

    }

    await user.save();

    alert("User info saved successfully!");

    openUserInfo();

}

createItem = async () => {

    if (createItemFile.files.length == 0){

        alert("Please select a file!");

        return;

    } else if (createItemNameField.value.length == 0){

        alert("Please give the item a name!");

        return;

    }

const nftFile = new Moralis.File("nftFile.webp", createItemFile.files[0]);

await nftFile.saveIPFS();

const nftFilePath = nftFile.ipfs();

const nftFileHash= nftFile.hash();

const metadata = {

    name: createItemNameField.value,

    description: createItemDescriptionField.value,

    image: nftFilePath,

};

const nftFileMetadataFile = new Moralis.File("metadata.json", {base64 : btoa(JSON.stringify(metadata))});

await nftFileMetadataFile.saveIPFS();

const nftFileMetadataFilePath = nftFileMetadataFile.ipfs();

const nftFileMetadataFileHash = nftFileMetadataFile.hash();

const nftId = await mintNft(nftFileMetadataFilePath);

const Item = Moralis.Object.extend("Item");

const item = new Item();

item.set('name', createItemNameField.value);

item.set('description', createItemDescriptionField.value);

item.set('nftFilePath', nftFilePath);

item.set('nftFileHash', nftFileHash);

item.set('metadataFilePath', nftFileMetadataFilepath);

item.set('metadataFileHash', nftFileMetadataFileHash);

item.set('nftId', nftId);

item.set('nftContractAddress', TOKEN_CONTRACT_ADDRESS);

await item.save();

console.log(item);

}

mintNft = async (metadataUrl) => {

    const receipt = await tokenContract.methods.createItem(metadataUrl).send({from: ethereum.selectedAddress});

    console.log(receipt);

    return receipt.events.Transfer.returnValues.tokenId;

}

hideElement = (element) => element.style.display = "none";

showElement = (element) => element.style.display = "block";

//Navbar

const userConnectButton = document.getElementById("btnConnect");

userConnectButton.onclick = login;

const userProfileButton = document.getElementById("btnUserInfo");

userProfileButton.onclick = openUserInfo;

//Userinfo

const userInfo = document.getElementById("userInfo");

const userNameField = document.getElementById("txtUsername");

const userEmailField = document.getElementById("txtEmail");

const userAvatarImg = document.getElementById("imgAvatar");

const userAvatarFile = document.getElementById("fileAvatar");

document.getElementById("btnCloseUserInfo").onclick = () => hideElement(userInfo);

document.getElementById("btnLogOut").onclick = logout;

document.getElementById("btnSaveUserInfo").onclick = saveUserInfo;

//Item Creation

const createItemForm = document.getElementById("createItem");

const createItemNameField = document.getElementById("txtCreateItemName");

const createItemDescriptionField = document.getElementById("txtCreateItemDescription");

const createItemPriceField = document.getElementById("numCreateItemPrice");

const createItemStatusField = document.getElementById("selectCreateItemStatus");

const createItemFile = document.getElementById("fileCreateItemFile");

const openCreateItemButton = document.getElementById("btnOpenCreateItem");

openCreateItemButton.onclick = () => showElement(createItemForm);

document.getElementById("btnCloseCreateItem").onclick = () => hideElement(createItemForm);

document.getElementById("btnCreateItem").onclick = createItem;

init();

You need to check where tokenContract is being used, this variable hasn’t been defined or created. Did you copy in the right code for main.js? It has other errors like MetaMask no longer injects web3 which means you have to create a web3.js instance.

web3 = new Web3(web3.currentProvider); // create instance

window.tokenContract = new web3.eth.Contract(
  tokenContractAbi,
  TOKEN_CONTRACT_ADDRESS
);
1 Like

Hi Glad
Thanks for quick reply.
I was able to fix the issue.
Cheers