如何修复错误 Class extends value undefined is not a constructor or null

问题描述 投票：0回答：1

导入时

import { useUmi } from '../../../../components/mint/umi';
import { useSplMinter } from '../../../../components/mint/tokenMinting';

我在令牌创建文件中收到错误。 错误：

Class extends value undefined is not a constructor or null
TypeError: Class extends value undefined is not a constructor or null
    at ./node_modules/@metaplex-foundation/mpl-token-metadata/dist/src/errors.js (http://192.168.0.222:3000/static/js/bundle.js:1873:40)
    at options.factory (http://192.168.0.222:3000/static/js/bundle.js:118516:31)
    at __webpack_require__ (http://192.168.0.222:3000/static/js/bundle.js:117945:32)
    at fn (http://192.168.0.222:3000/static/js/bundle.js:118174:21)
    at ./node_modules/@metaplex-foundation/mpl-token-metadata/dist/src/hooked/metadataDelegateRoleSeed.js (http://192.168.0.222:3000/static/js/bundle.js:20702:18)
    at options.factory (http://192.168.0.222:3000/static/js/bundle.js:118516:31)
    at __webpack_require__ (http://192.168.0.222:3000/static/js/bundle.js:117945:32)
    at fn (http://192.168.0.222:3000/static/js/bundle.js:118174:21)
    at ./node_modules/@metaplex-foundation/mpl-token-metadata/dist/src/hooked/index.js (http://192.168.0.222:3000/static/js/bundle.js:20682:14)
    at options.factory (http://192.168.0.222:3000/static/js/bundle.js:118516:31)

我知道问题出在 

@metaplex-foundation/mpl-token-metadata
库中，但我不知道如何消除这个错误。这是我的代码：

import React, {useRef, useState} from 'react';
import { uploadMetadata } from "../../../../action/tokens_api";
import Add from '../../../../assets/images/icons/add.svg';
import './styles/styles.css';
import { useUmi } from '../../../../components/mint/umi';
import { useSplMinter } from '../../../../components/mint/tokenMinting';

const TokenCreator = () => {    const fileInputRef = useRef(null);
    const [name, setName] = useState('');
    const [symbol, setSymbol] = useState('');
    const [sypply, setSypply] = useState('');
    const [description, setDescription] = useState('');
    const [file, setFile] = useState(null);

    const umi = useUmi('network', 'wallet');
    const splMinter = useSplMinter(umi);

    const handleFileInputClick = () => {
        fileInputRef.current.click();
    };
    const handleFileInputChange = (event) => {
        const file = event.target.files[0];
        setFile(file);
    };
    const handleCreateToken = async () => {
        try {
            const metadataUrl = await uploadMetadata(file, name, description, symbol);
            console.log('Metadata URL:', metadataUrl);
            const mintResult = await splMinter.create({
                name: name,
                symbol: symbol,
                uri: metadataUrl
            }, '3000000000000000000');

            console.log('Mint Result:', mintResult);
        } catch (error) {
            console.error('Error creating token:', error);
        }
    };

    return(
        <div className='creator'>
            form here
        </div>
    )}

export default TokenCreator;

import { createUmi } from '@metaplex-foundation/umi-bundle-defaults';
import { mplTokenMetadata } from '@metaplex-foundation/mpl-token-metadata';
import { walletAdapterIdentity } from '@metaplex-foundation/umi-signer-wallet-adapters';
import API_KEY from'../../action/API_KEY/api_key';

export const useUmi = (network, wallet) => {
    return (
        createUmi(`https://${network}.helius-rpc.com/?api-key=${API_KEY}`)            
            .use(mplTokenMetadata())
            .use(walletAdapterIdentity(wallet))
    );
};

import { percentAmount, generateSigner, createBigInt } from '@metaplex-foundation/umi';
import { fromWeb3JsInstruction } from '@metaplex-foundation/umi-web3js-adapters';
import { ComputeBudgetProgram } from '@solana/web3.js';
import { TokenStandard, createAndMint } from '@metaplex-foundation/mpl-token-metadata';

export const useSplMinter = (umi) => {
    const create = async (metadata = { name: '', symbol: '', uri: '' }, amount = '0') => {
        const mint = generateSigner(umi);
        const priceIx = ComputeBudgetProgram.setComputeUnitPrice({ microLamports: 1000000 });

        const transaction = createAndMint(umi, {
            mint,
            authority: umi.identity,
            name: metadata.name,
            symbol: metadata.symbol,
            uri: metadata.uri,
            sellerFeeBasisPoints: percentAmount(0),
            decimals: 9,
            amount: createBigInt(amount),
            tokenOwner: umi.identity.publicKey,
            tokenStandard: TokenStandard.Fungible,
        }).prepend({
            instruction: fromWeb3JsInstruction(priceIx),
            signers: [],
            bytesCreatedOnChain: 0,
        });

        const res = await transaction.sendAndConfirm(umi);

        return { mint: mint.publicKey.toString(), ...res };
    };

    return { create };
};

如有任何帮助，我将不胜感激

javascript reactjs solana-web3js metaplex
1个回答
0
投票

因此，我意识到 RCA 不支持 .cjs，因此无法从 .cjs 导入模块。要处理此错误，您必须首先安装模块：

npm i buffer crypto-browserify https-browserify stream stream-browserify process stream-http react-app-rewired
.

之后将其添加到package.json

"browser": {
    "path": false,
    "stream": false,
    "http": false,
    "https": false
},

也改变 从这里

"start": "react-scripts start",
"build": "react-scripts build",
"test": "react-scripts test",

到此

"start": "react-app-rewired start",
"build": "react-app-rewired build",
"test": "react-app-rewired test",

在项目的根目录中创建一个文件 config-overrides.js，其内容为：

const webpack = require("webpack");
const getCacheIdentifier = require("react-dev-utils/getCacheIdentifier");

module.exports = function override(config, webpackEnv) {
  console.log("Overriding webpack config...");

  // Set up environment flags
  const isEnvDevelopment = webpackEnv === "development";
  const isEnvProduction = webpackEnv === "production";
  const shouldUseSourceMap = process.env.GENERATE_SOURCEMAP !== "false";

  // Configure fallbacks for Node environment
  const fallback = config.resolve.fallback || {};
  Object.assign(fallback, {
    crypto: require.resolve("crypto-browserify"),
    stream: require.resolve("stream-browserify"),
    assert: require.resolve("assert"),
    http: require.resolve("stream-http"),
    https: require.resolve("https-browserify"),
    os: require.resolve("os-browserify"),
    url: require.resolve("url"),
    zlib: require.resolve("browserify-zlib"),
  });
  config.resolve.fallback = fallback;

  // Configure plugins
  config.plugins = (config.plugins || []).concat([
    new webpack.ProvidePlugin({
      process: "process/browser",
      Buffer: ["buffer", "Buffer"],
    }),
  ]);

  // Ignore certain warnings
  config.ignoreWarnings = [/Failed to parse source map/];

  // Add source-map loader
  config.module.rules.push({
    test: /\.(js|mjs|jsx)$/,
    enforce: "pre",
    loader: require.resolve("source-map-loader"),
    resolve: {
      fullySpecified: false,
    },
  });

  // Modify Babel loader configuration
  const loaders = config.module.rules.find((rule) =>
    Array.isArray(rule.oneOf)
  ).oneOf;
  loaders.splice(loaders.length - 1, 0, {
    test: /\.(js|mjs|cjs)$/,
    exclude: /@babel(?:\/|\\{1,2})runtime/,
    loader: require.resolve("babel-loader"),
    options: {
      babelrc: false,
      configFile: false,
      compact: false,
      presets: [
        [
          require.resolve("babel-preset-react-app/dependencies"),
          { helpers: true },
        ],
      ],
      cacheDirectory: true,
      cacheCompression: false,
      cacheIdentifier: getCacheIdentifier(
        isEnvProduction ? "production" : isEnvDevelopment && "development",
        [
          "babel-plugin-named-asset-import",
          "babel-preset-react-app",
          "react-dev-utils",
          "react-scripts",
        ]
      ),
      sourceMaps: shouldUseSourceMap,
      inputSourceMap: shouldUseSourceMap,
    },
  });

  return config;
};
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