web3：无法读取新ethers之后的null的属性。

发布于 2025-01-24 17:02:36 字数 1825 浏览 3 评论 0原文

实例化之后，我正试图使用智能合约。但是，我有一个错误：

未被发现（在承诺中）TypeError：无法读取null的属性（阅读“呼叫”）

我认为我在实例化之后就无法访问这些功能，但似乎并非如此。还可以是什么？有人已经有类似的问题吗？

当前代码：

import React, { useEffect, useState } from 'react';
import Head from 'next/head';

import { useWeb3React } from '@web3-react/core';
import NFTCollectionArtifact from 'artifacts/contracts/NFTCollection.sol/NFTCollection.json';
import { Contract, ethers, Signer } from 'ethers';
import { Provider } from '@openmint/utils/provider';

export const Index = () => {
  const context = useWeb3React<Provider>();
  const { library } = context;

  const [contractInstance, setContractInstance] = useState<Contract | undefined>();
  const [signer, setSigner] = useState<Signer>();
  const [name, setName] = useState<String>('');

  useEffect(() => {

    const address = '0x5FbDB2315678afecb367f032d93F642f64180aa3';
    const nftCollection = new ethers.Contract(
      address,
      NFTCollectionArtifact.abi,
      signer
    );

    setContractInstance(nftCollection);
  }, []);

  useEffect(() => {
    if(!contractInstance) return;

    const setContractName = async () => {
      try{
        console.log(await contractInstance?.name());
        setName(await contractInstance?.name());
      } catch(e){
        console.error('my error', e);
      }
    }
  
    setContractName();
  }, [contractInstance]);

  useEffect((): void => {
    if (!library) {
      setSigner(undefined);
      return;
    }

    setSigner(library.getSigner());
  }, [library]);

  return (
    <>
      <Head>
        <title>Preview NFTs</title>
      </Head>
    </>
  );
};

export default Index;

原文

I am trying to use a smart contract just after I instantiate it. However, I get an error:

Uncaught (in promise) TypeError: Cannot read properties of null
(reading 'call')

I thought I did not have access to the functions just after instantiating it, but it does not seem to be it. What else could it be? Someone already had a similar problem?

Current code:

import React, { useEffect, useState } from 'react';
import Head from 'next/head';

import { useWeb3React } from '@web3-react/core';
import NFTCollectionArtifact from 'artifacts/contracts/NFTCollection.sol/NFTCollection.json';
import { Contract, ethers, Signer } from 'ethers';
import { Provider } from '@openmint/utils/provider';

export const Index = () => {
  const context = useWeb3React<Provider>();
  const { library } = context;

  const [contractInstance, setContractInstance] = useState<Contract | undefined>();
  const [signer, setSigner] = useState<Signer>();
  const [name, setName] = useState<String>('');

  useEffect(() => {

    const address = '0x5FbDB2315678afecb367f032d93F642f64180aa3';
    const nftCollection = new ethers.Contract(
      address,
      NFTCollectionArtifact.abi,
      signer
    );

    setContractInstance(nftCollection);
  }, []);

  useEffect(() => {
    if(!contractInstance) return;

    const setContractName = async () => {
      try{
        console.log(await contractInstance?.name());
        setName(await contractInstance?.name());
      } catch(e){
        console.error('my error', e);
      }
    }
  
    setContractName();
  }, [contractInstance]);

  useEffect((): void => {
    if (!library) {
      setSigner(undefined);
      return;
    }

    setSigner(library.getSigner());
  }, [library]);

  return (
    <>
      <Head>
        <title>Preview NFTs</title>
      </Head>
    </>
  );
};

export default Index;

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茶底世界 2025-01-31 17:02:36

好的，我仍然不明白以下解决方案有效的全部图片，但是如果外面有人有类似的问题，这对我有用：

useEffect((): void => {
    if (!contractInstance) {
      return;
    }

    async function getStatus(MyContract: Contract): Promise<void> {
      const name = await MyContract.name();

      const newStatus: StatusInterface = {
        ...status,
        name
      };

      console.log('newStatus', newStatus);
      if (!isEqual(status, newStatus)) {
        setStatus(newStatus);
      }
    }

    getStatus(contractInstance);
  }, [contractInstance, status, account]);

只有在有差异的
情况下改变状态对于功能，

我的理解是这是一个范围问题。

Ok, I still do not understand the whole picture of why the following solution works, but if anyone out there is having a similar issue, this was what worked for me:

useEffect((): void => {
    if (!contractInstance) {
      return;
    }

    async function getStatus(MyContract: Contract): Promise<void> {
      const name = await MyContract.name();

      const newStatus: StatusInterface = {
        ...status,
        name
      };

      console.log('newStatus', newStatus);
      if (!isEqual(status, newStatus)) {
        setStatus(newStatus);
      }
    }

    getStatus(contractInstance);
  }, [contractInstance, status, account]);

Only change the state if there is a difference
Pass the contract as a prop for the function

My understanding is that this was a scope issue.

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〃安静 2025-01-31 17:02:36

确保您的环境配置已正确设置帐户。就我而言，这是因为我有一个额外的wallet_private_key =使用Ethers + Harthat时在我的.env中设置的行。

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稀香 2025-01-31 17:02:36

通常可以看到签名对象无效/未定义。任何具有无效签名对象的活动（例如合同创建，呼叫，发送事务等）都会有错误：TypeError：无法在合同中读取Null（读取'call'）的属性。（node_modules@ethersproject \ Contracts \ src.ts \ index.ts：397：47）...

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猥琐帝 2025-01-31 17:02:36

以防万一 - 如果您在创建合同对象时根本不提供第三个参数，则可能发生：

contract = new ethers.Contract(address, abi);

正确的方法是：

contract = new ethers.Contract(address, abi, providerOrSigner);

我希望有更清晰的错误消息，字面上说您没有提供签名者/提供者。与其在合同对象的创建上默默地接受此内容，然后以毫无意义的堆栈跟踪读取null的属性（读取'call'）。

Just in case - this can happen if you simply don't provide a third parameter when creating a contract object:

contract = new ethers.Contract(address, abi);

The proper way would be:

contract = new ethers.Contract(address, abi, providerOrSigner);

I wish there was a clearer error message that literally said you did not supply a signer/provider. Instead of silently accepting this on contract object creation, and then later throwing the cryptic TypeError: Cannot read properties of null (reading 'call') with a meaningless stack trace.

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~没有更多了~