Ошибка React webpack при загрузке изображения во время выполнения

#javascript #reactjs #webpack

#javascript #reactjs #webpack

Вопрос:

Я пытаюсь загрузить изображение во время выполнения в моем компоненте react.

Изображения хранятся в папке src / assets

 var bg=require('../../../assets/plot1.jpg');
return(
<div  style ={ { backgroundImage: "url(" bg ")"} }>  </div>
);
  

Этот код работает и загружает изображение. однако я хочу получить путь к изображению во время выполнения. итак, если я изменю свой код, как показано ниже

  var bg=require(props.bgImg);
  

где значение props.bgImg равно ../../../assets/plot1.jpg . Затем я получаю приведенную ниже ошибку

Ошибка

     Error: Cannot find module '../../../assets/plot1.jpg'
    webpackEmptyContext

Array.webpackJsonpCallback [as push]
D:/data/sdf/webpack/bootstrap:32
  29 |  deferredModules.push.apply(deferredModules, executeModules || []);
  30 | 
  31 |  // run deferred modules when all chunks ready
> 32 |  return checkDeferredModules();
     | ^  33 | };
  34 | function checkDeferredModules() {
  35 |  var resu<
  

Будет ли мое изображение сохранено по другому пути после компиляции.
Как я могу указать путь во время выполнения.

Мой package.json

    "node-sass": "^4.14.1",
    "react": "^16.13.1",
    "react-dom": "^16.13.1",
    "react-redux": "^7.2.1",
    "react-router-dom": "^5.2.0",
    "react-scripts": "3.4.3",
    "redux": "^4.0.5"
  

добавлено webpack.config.js

 // @remove-on-eject-begin
/**
 * Copyright (c) 2015-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
// @remove-on-eject-end
'use strict';

const fs = require('fs');
const path = require('path');
const webpack = require('webpack');
const resolve = require('resolve');
const PnpWebpackPlugin = require('pnp-webpack-plugin');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const CaseSensitivePathsPlugin = require('case-sensitive-paths-webpack-plugin');
const InlineChunkHtmlPlugin = require('react-dev-utils/InlineChunkHtmlPlugin');
const TerserPlugin = require('terser-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');
const safePostCssParser = require('postcss-safe-parser');
const ManifestPlugin = require('webpack-manifest-plugin');
const InterpolateHtmlPlugin = require('react-dev-utils/InterpolateHtmlPlugin');
const WorkboxWebpackPlugin = require('workbox-webpack-plugin');
const WatchMissingNodeModulesPlugin = require('react-dev-utils/WatchMissingNodeModulesPlugin');
const ModuleScopePlugin = require('react-dev-utils/ModuleScopePlugin');
const getCSSModuleLocalIdent = require('react-dev-utils/getCSSModuleLocalIdent');
const paths = require('./paths');
const modules = require('./modules');
const getClientEnvironment = require('./env');
const ModuleNotFoundPlugin = require('react-dev-utils/ModuleNotFoundPlugin');
const ForkTsCheckerWebpackPlugin = require('react-dev-utils/ForkTsCheckerWebpackPlugin');
const typescriptFormatter = require('react-dev-utils/typescriptFormatter');
// @remove-on-eject-begin
const getCacheIdentifier = require('react-dev-utils/getCacheIdentifier');
// @remove-on-eject-end
const postcssNormalize = require('postcss-normalize');

const appPackageJson = require(paths.appPackageJson);

// Source maps are resource heavy and can cause out of memory issue for large source files.
const shouldUseSourceMap = process.env.GENERATE_SOURCEMAP !== 'false';
// Some apps do not need the benefits of saving a web request, so not inlining the chunk
// makes for a smoother build process.
const shouldInlineRuntimeChunk = process.env.INLINE_RUNTIME_CHUNK !== 'false';

const isExtendingEslintConfig = process.env.EXTEND_ESLINT === 'true';

const imageInlineSizeLimit = parseInt(
  process.env.IMAGE_INLINE_SIZE_LIMIT || '10000'
);

// Check if TypeScript is setup
const useTypeScript = fs.existsSync(paths.appTsConfig);

// style files regexes
const cssRegex = /.css$/;
const cssModuleRegex = /.module.css$/;
const sassRegex = /.(scss|sass)$/;
const sassModuleRegex = /.module.(scss|sass)$/;

// This is the production and development configuration.
// It is focused on developer experience, fast rebuilds, and a minimal bundle.
module.exports = function(webpackEnv) {
  const isEnvDevelopment = webpackEnv === 'development';
  const isEnvProduction = webpackEnv === 'production';

  // Variable used for enabling profiling in Production
  // passed into alias object. Uses a flag if passed into the build command
  const isEnvProductionProfile =
    isEnvProduction amp;amp; process.argv.includes('--profile');

  // We will provide `paths.publicUrlOrPath` to our app
  // as %PUBLIC_URL% in `index.html` and `process.env.PUBLIC_URL` in JavaScript.
  // Omit trailing slash as %PUBLIC_URL%/xyz looks better than %PUBLIC_URL%xyz.
  // Get environment variables to inject into our app.
  const env = getClientEnvironment(paths.publicUrlOrPath.slice(0, -1));

  // common function to get style loaders
  const getStyleLoaders = (cssOptions, preProcessor) => {
    const loaders = [
      isEnvDevelopment amp;amp; require.resolve('style-loader'),
      isEnvProduction amp;amp; {
        loader: MiniCssExtractPlugin.loader,
        // css is located in `static/css`, use '../../' to locate index.html folder
        // in production `paths.publicUrlOrPath` can be a relative path
        options: paths.publicUrlOrPath.startsWith('.')
          ? { publicPath: '../../' }
          : {},
      },
      {
        loader: require.resolve('css-loader'),
        options: cssOptions,
      },
      {
        // Options for PostCSS as we reference these options twice
        // Adds vendor prefixing based on your specified browser support in
        // package.json
        loader: require.resolve('postcss-loader'),
        options: {
          // Necessary for external CSS imports to work
          // https://github.com/facebook/create-react-app/issues/2677
          ident: 'postcss',
          plugins: () => [
            require('postcss-flexbugs-fixes'),
            require('postcss-preset-env')({
              autoprefixer: {
                flexbox: 'no-2009',
              },
              stage: 3,
            }),
            // Adds PostCSS Normalize as the reset css with default options,
            // so that it honors browserslist config in package.json
            // which in turn let's users customize the target behavior as per their needs.
            postcssNormalize(),
          ],
          sourceMap: isEnvProduction amp;amp; shouldUseSourceMap,
        },
      },
    ].filter(Boolean);
    if (preProcessor) {
      loaders.push(
        {
          loader: require.resolve('resolve-url-loader'),
          options: {
            sourceMap: isEnvProduction amp;amp; shouldUseSourceMap,
          },
        },
        {
          loader: require.resolve(preProcessor),
          options: {
            sourceMap: true,
          },
        }
      );
    }
    return loaders;
  };

  return {
    mode: isEnvProduction ? 'production' : isEnvDevelopment amp;amp; 'development',
    // Stop compilation early in production
    bail: isEnvProduction,
    devtool: isEnvProduction
      ? shouldUseSourceMap
        ? 'source-map'
        : false
      : isEnvDevelopment amp;amp; 'cheap-module-source-map',
    // These are the "entry points" to our application.
    // This means they will be the "root" imports that are included in JS bundle.
    entry: [
      
      isEnvDevelopment amp;amp;
        require.resolve('react-dev-utils/webpackHotDevClient'),
      // Finally, this is your app's code:
      paths.appIndexJs,
      // We include the app code last so that if there is a runtime error during
      // initialization, it doesn't blow up the WebpackDevServer client, and
      // changing JS code would still trigger a refresh.
    ].filter(Boolean),
    output: {
      // The build folder.
      path: isEnvProduction ? paths.appBuild : undefined,
      // Add /* filename */ comments to generated require()s in the output.
      pathinfo: isEnvDevelopment,
      // There will be one main bundle, and one file per asynchronous chunk.
      // In development, it does not produce real files.
      filename: isEnvProduction
        ? 'static/js/[name].[contenthash:8].js'
        : isEnvDevelopment amp;amp; 'static/js/bundle.js',
      // TODO: remove this when upgrading to webpack 5
      futureEmitAssets: true,
      // There are also additional JS chunk files if you use code splitting.
      chunkFilename: isEnvProduction
        ? 'static/js/[name].[contenthash:8].chunk.js'
        : isEnvDevelopment amp;amp; 'static/js/[name].chunk.js',
      // webpack uses `publicPath` to determine where the app is being served from.
      // It requires a trailing slash, or the file assets will get an incorrect path.
      // We inferred the "public path" (such as / or /my-project) from homepage.
      publicPath: paths.publicUrlOrPath,
      // Point sourcemap entries to original disk location (format as URL on Windows)
      devtoolModuleFilenameTemplate: isEnvProduction
        ? info =>
            path
              .relative(paths.appSrc, info.absoluteResourcePath)
              .replace(/\/g, '/')
        : isEnvDevelopment amp;amp;
          (info => path.resolve(info.absoluteResourcePath).replace(/\/g, '/')),
      // Prevents conflicts when multiple webpack runtimes (from different apps)
      // are used on the same page.
      jsonpFunction: `webpackJsonp${appPackageJson.name}`,
      // this defaults to 'window', but by setting it to 'this' then
      // module chunks which are built will work in web workers as well.
      globalObject: 'this',
    },
    optimization: {
      minimize: isEnvProduction,
      minimizer: [
        // This is only used in production mode
        new TerserPlugin({
          terserOptions: {
            parse: {
              // We want terser to parse ecma 8 code. However, we don't want it
              // to apply any minification steps that turns valid ecma 5 code
              // into invalid ecma 5 code. This is why the 'compress' and 'output'
              // sections only apply transformations that are ecma 5 safe
              // https://github.com/facebook/create-react-app/pull/4234
              ecma: 8,
            },
            compress: {
              ecma: 5,
              warnings: false,

              comparisons: false,

              inline: 2,
            },
            mangle: {
              safari10: true,
            },
            // Added for profiling in devtools
            keep_classnames: isEnvProductionProfile,
            keep_fnames: isEnvProductionProfile,
            output: {
              ecma: 5,
              comments: false,
              // Turned on because emoji and regex is not minified properly using default
              // https://github.com/facebook/create-react-app/issues/2488
              ascii_only: true,
            },
          },
          sourceMap: shouldUseSourceMap,
        }),
        // This is only used in production mode
        new OptimizeCSSAssetsPlugin({
          cssProcessorOptions: {
            parser: safePostCssParser,
            map: shouldUseSourceMap
              ? {
                  // `inline: false` forces the sourcemap to be output into a
                  // separate file
                  inline: false,
                  // `annotation: true` appends the sourceMappingURL to the end of
                  // the css file, helping the browser find the sourcemap
                  annotation: true,
                }
              : false,
          },
          cssProcessorPluginOptions: {
            preset: ['default', { minifyFontValues: { removeQuotes: false } }],
          },
        }),
      ],

      splitChunks: {
        chunks: 'all',
        name: false,
      },
      // Keep the runtime chunk separated to enable long term caching
      // https://twitter.com/wSokra/status/969679223278505985
      // https://github.com/facebook/create-react-app/issues/5358
      runtimeChunk: {
        name: entrypoint => `runtime-${entrypoint.name}`,
      },
    },
    resolve: {

      modules: ['node_modules', paths.appNodeModules].concat(
        modules.additionalModulePaths || []
      ),

      extensions: paths.moduleFileExtensions
        .map(ext => `.${ext}`)
        .filter(ext => useTypeScript || !ext.includes('ts')),
      alias: {
        // Support React Native Web
        // https://www.smashingmagazine.com/2016/08/a-glimpse-into-the-future-with-react-native-for-web/
        'react-native': 'react-native-web',
        // Allows for better profiling with ReactDevTools
        ...(isEnvProductionProfile amp;amp; {
          'react-dom$': 'react-dom/profiling',
          'scheduler/tracing': 'scheduler/tracing-profiling',
        }),
        ...(modules.webpackAliases || {}),
      },
      plugins: [
        // Adds support for installing with Plug'n'Play, leading to faster installs and adding
        // guards against forgotten dependencies and such.
        PnpWebpackPlugin,
 
        new ModuleScopePlugin(paths.appSrc, [paths.appPackageJson]),
      ],
    },
    resolveLoader: {
      plugins: [
        // Also related to Plug'n'Play, but this time it tells webpack to load its loaders
        // from the current package.
        PnpWebpackPlugin.moduleLoader(module),
      ],
    },
    module: {
      strictExportPresence: true,
      rules: [
        // Disable require.ensure as it's not a standard language feature.
        { parser: { requireEnsure: false } },

        // First, run the linter.
        // It's important to do this before Babel processes the JS.
        {
          test: /.(js|mjs|jsx|ts|tsx)$/,
          enforce: 'pre',
          use: [
            {
              options: {
                cache: true,
                formatter: require.resolve('react-dev-utils/eslintFormatter'),
                eslintPath: require.resolve('eslint'),
                resolvePluginsRelativeTo: __dirname,
                // @remove-on-eject-begin
                ignore: isExtendingEslintConfig,
                baseConfig: isExtendingEslintConfig
                  ? undefined
                  : {
                      extends: [require.resolve('eslint-config-react-app')],
                    },
                useEslintrc: isExtendingEslintConfig,
                // @remove-on-eject-end
              },
              loader: require.resolve('eslint-loader'),
            },
          ],
          include: paths.appSrc,
        },
        {

          oneOf: [
          
            {
              test: [/.bmp$/, /.gif$/, /.jpe?g$/, /.png$/],
              loader: require.resolve('url-loader'),
              options: {
                limit: imageInlineSizeLimit,
                name: 'static/media/[name].[hash:8].[ext]',
              },
            },
            // Process application JS with Babel.
            // The preset includes JSX, Flow, TypeScript, and some ESnext features.
            {
              test: /.(js|mjs|jsx|ts|tsx)$/,
              include: paths.appSrc,
              loader: require.resolve('babel-loader'),
              options: {
                customize: require.resolve(
                  'babel-preset-react-app/webpack-overrides'
                ),
                // @remove-on-eject-begin
                babelrc: false,
                configFile: false,
                presets: [require.resolve('babel-preset-react-app')],
                // Make sure we have a unique cache identifier, erring on the
                // side of caution.
                // We remove this when the user ejects because the default
                // is sane and uses Babel options. Instead of options, we use
                // the react-scripts and babel-preset-react-app versions.
                cacheIdentifier: getCacheIdentifier(
                  isEnvProduction
                    ? 'production'
                    : isEnvDevelopment amp;amp; 'development',
                  [
                    'babel-plugin-named-asset-import',
                    'babel-preset-react-app',
                    'react-dev-utils',
                    'react-scripts',
                  ]
                ),
                // @remove-on-eject-end
                plugins: [
                  [
                    require.resolve('babel-plugin-named-asset-import'),
                    {
                      loaderMap: {
                        svg: {
                          ReactComponent:
                            '@svgr/webpack?-svgo, titleProp, ref![path]',
                        },
                      },
                    },
                  ],
                ],
                // This is a feature of `babel-loader` for webpack (not Babel itself).
                // It enables caching results in ./node_modules/.cache/babel-loader/
                // directory for faster rebuilds.
                cacheDirectory: true,
                // See #6846 for context on why cacheCompression is disabled
                cacheCompression: false,
                compact: isEnvProduction,
              },
            },
            // Process any JS outside of the app with Babel.
            // Unlike the application JS, we only compile the standard ES features.
            {
              test: /.(js|mjs)$/,
              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,
                // See #6846 for context on why cacheCompression is disabled
                cacheCompression: false,
                // @remove-on-eject-begin
                cacheIdentifier: getCacheIdentifier(
                  isEnvProduction
                    ? 'production'
                    : isEnvDevelopment amp;amp; 'development',
                  [
                    'babel-plugin-named-asset-import',
                    'babel-preset-react-app',
                    'react-dev-utils',
                    'react-scripts',
                  ]
                ),
        
                sourceMaps: shouldUseSourceMap,
                inputSourceMap: shouldUseSourceMap,
              },
            },
     
            {
              test: cssRegex,
              exclude: cssModuleRegex,
              use: getStyleLoaders({
                importLoaders: 1,
                sourceMap: isEnvProduction amp;amp; shouldUseSourceMap,
              }),

              sideEffects: true,
            },
            // Adds support for CSS Modules (https://github.com/css-modules/css-modules)
            // using the extension .module.css
            {
              test: cssModuleRegex,
              use: getStyleLoaders({
                importLoaders: 1,
                sourceMap: isEnvProduction amp;amp; shouldUseSourceMap,
                modules: {
                  getLocalIdent: getCSSModuleLocalIdent,
                },
              }),
            },
            // Opt-in support for SASS (using .scss or .sass extensions).
            // By default we support SASS Modules with the
            // extensions .module.scss or .module.sass
            {
              test: sassRegex,
              exclude: sassModuleRegex,
              use: getStyleLoaders(
                {
                  importLoaders: 3,
                  sourceMap: isEnvProduction amp;amp; shouldUseSourceMap,
                },
                'sass-loader'
              ),
           
              sideEffects: true,
            },
            // Adds support for CSS Modules, but using SASS
            // using the extension .module.scss or .module.sass
            {
              test: sassModuleRegex,
              use: getStyleLoaders(
                {
                  importLoaders: 3,
                  sourceMap: isEnvProduction amp;amp; shouldUseSourceMap,
                  modules: {
                    getLocalIdent: getCSSModuleLocalIdent,
                  },
                },
                'sass-loader'
              ),
            },
           
            {
              loader: require.resolve('file-loader'),
              // Exclude `js` files to keep "css" loader working as it injects
              // its runtime that would otherwise be processed through "file" loader.
              // Also exclude `html` and `json` extensions so they get processed
              // by webpacks internal loaders.
              exclude: [/.(js|mjs|jsx|ts|tsx)$/, /.html$/, /.json$/],
              options: {
                name: 'static/media/[name].[hash:8].[ext]',
              },
            },
            // ** STOP ** Are you adding a new loader?
            // Make sure to add the new loader(s) before the "file" loader.
          ],
        },
      ],
    },
    plugins: [
      // Generates an `index.html` file with the <script> injected.
      new HtmlWebpackPlugin(
        Object.assign(
          {},
          {
            inject: true,
            template: paths.appHtml,
          },
          isEnvProduction
            ? {
                minify: {
                  removeComments: true,
                  collapseWhitespace: true,
                  removeRedundantAttributes: true,
                  useShortDoctype: true,
                  removeEmptyAttributes: true,
                  removeStyleLinkTypeAttributes: true,
                  keepClosingSlash: true,
                  minifyJS: true,
                  minifyCSS: true,
                  minifyURLs: true,
                },
              }
            : undefined
        )
      ),
      // Inlines the webpack runtime script. This script is too small to warrant
      // a network request.
      // https://github.com/facebook/create-react-app/issues/5358
      isEnvProduction amp;amp;
        shouldInlineRuntimeChunk amp;amp;
        new InlineChunkHtmlPlugin(HtmlWebpackPlugin, [/runtime-. [.]js/]),

      new InterpolateHtmlPlugin(HtmlWebpackPlugin, env.raw),
      // This gives some necessary context to module not found errors, such as
      // the requesting resource.
      new ModuleNotFoundPlugin(paths.appPath),
      
      new webpack.DefinePlugin(env.stringified),
      // This is necessary to emit hot updates (currently CSS only):
      isEnvDevelopment amp;amp; new webpack.HotModuleReplacementPlugin(),
      
      isEnvDevelopment amp;amp; new CaseSensitivePathsPlugin(),
      
      isEnvDevelopment amp;amp;
        new WatchMissingNodeModulesPlugin(paths.appNodeModules),
      isEnvProduction amp;amp;
        new MiniCssExtractPlugin({
          // Options similar to the same options in webpackOptions.output
          // both options are optional
          filename: 'static/css/[name].[contenthash:8].css',
          chunkFilename: 'static/css/[name].[contenthash:8].chunk.css',
        }),
      // Generate an asset manifest file with the following content:
      // - "files" key: Mapping of all asset filenames to their corresponding
      //   output file so that tools can pick it up without having to parse
      //   `index.html`
      // - "entrypoints" key: Array of files which are included in `index.html`,
      //   can be used to reconstruct the HTML if necessary
      new ManifestPlugin({
        fileName: 'asset-manifest.json',
        publicPath: paths.publicUrlOrPath,
        generate: (seed, files, entrypoints) => {
          const manifestFiles = files.reduce((manifest, file) => {
            manifest[file.name] = file.path;
            return manifest;
          }, seed);
          const entrypointFiles = entrypoints.main.filter(
            fileName => !fileName.endsWith('.map')
          );

          return {
            files: manifestFiles,
            entrypoints: entrypointFiles,
          };
        },
      }),

      new webpack.IgnorePlugin(/^./locale$/, /moment$/),
      // Generate a service worker script that will precache, and keep up to date,
      // the HTML amp; assets that are part of the webpack build.
      isEnvProduction amp;amp;
        new WorkboxWebpackPlugin.GenerateSW({
          clientsClaim: true,
          exclude: [/.map$/, /asset-manifest.json$/],
          importWorkboxFrom: 'cdn',
          navigateFallback: paths.publicUrlOrPath   'index.html',
          navigateFallbackBlacklist: [
            // Exclude URLs starting with /_, as they're likely an API call
            new RegExp('^/_'),
            // Exclude any URLs whose last part seems to be a file extension
            // as they're likely a resource and not a SPA route.
            // URLs containing a "?" character won't be blacklisted as they're likely
            // a route with query params (e.g. auth callbacks).
            new RegExp('/[^/?] \.[^/] $'),
          ],
        }),
      // TypeScript type checking
      useTypeScript amp;amp;
        new ForkTsCheckerWebpackPlugin({
          typescript: resolve.sync('typescript', {
            basedir: paths.appNodeModules,
          }),
          async: isEnvDevelopment,
          useTypescriptIncrementalApi: true,
          checkSyntacticErrors: true,
          resolveModuleNameModule: process.versions.pnp
            ? `${__dirname}/pnpTs.js`
            : undefined,
          resolveTypeReferenceDirectiveModule: process.versions.pnp
            ? `${__dirname}/pnpTs.js`
            : undefined,
          tsconfig: paths.appTsConfig,
          reportFiles: [
            '**',
            '!**/__tests__/**',
            '!**/?(*.)(spec|test).*',
            '!**/src/setupProxy.*',
            '!**/src/setupTests.*',
          ],
          silent: true,
          // The formatter is invoked directly in WebpackDevServerUtils during development
          formatter: isEnvProduction ? typescriptFormatter : undefined,
        }),
    ].filter(Boolean),
    
    node: {
      module: 'empty',
      dgram: 'empty',
      dns: 'mock',
      fs: 'empty',
      http2: 'empty',
      net: 'empty',
      tls: 'empty',
      child_process: 'empty',
    },
    // Turn off performance processing because we utilize
    // our own hints via the FileSizeReporter
    performance: false,
  };
};  

Комментарии:

1. Какой загрузчик webpack вы используете для изображений? file-loader должен вернуть URL-адрес изображения, который затем может быть использован во время выполнения.

2. Не могли бы вы, пожалуйста, предоставить более подробную информацию о поиске URL-адреса изображения. и как я могу найти загрузчик webpack

3. Синтаксис тот же, но конфигурация webpack отличается. Можете ли вы опубликовать конфигурацию вашего webpack?

4. добавлено webpackDevServer.config.js

5. Это конфигурация из create-react-app ? У этого нет всей конфигурации. Вероятно, должна быть другая config/webpack.config.js .

Ответ №1:

Вы загружаете путь к изображению динамически, но во время выполнения и в зависимости от конфигурации вашего webpack пути к вашим ресурсам в пакете могут отличаться от того, что указано в вашем коде.

Вот url-loader конфигурация по умолчанию в webpack для приложений, созданных create-react-app :

 {
    test: [/.bmp$/, /.gif$/, /.jpe?g$/, /.png$/],
    loader: require.resolve('file-loader'),
    options: {
        name: 'static/media/[name].[hash:8].[ext]',
    },
},
  

Как вы можете видеть, совпадающие файлы test окажутся в static/media/[name].[hash:8].[ext] . Таким образом, ваше фоновое изображение будет сохранено как static/media/plot1.<some-hash>.jpg , которое отличается от пути, который вы передаете require через props , т.е. ../../../assets/plot1.jpg .

В первом случае ( var bg=require('../../../assets/plot1.jpg') ) webpack видит путь, обнаруживает изображение, преобразует его путь и присваивает преобразованный путь bg . Во втором случае значение props.bg неизвестно во время компиляции, поэтому webpack не обрабатывает его, из-за чего вашего изображения может не оказаться в ресурсах, или, если оно есть, его путь неизвестен вашему коду во время выполнения. Суть в том, что ваш код не должен полагаться на значения, которые будут изменены такими пакетами, как webpack, в процессе переноса.

Вы можете поместить пути к своим изображениям в объект, который обрабатывается webpack, а затем обратиться к ключам этого объекта, чтобы получить правильное изображение. Вот пример:

Поместите это где-нибудь за пределами ваших компонентов, возможно, в файл конфигурации или в вашу точку входа, везде, где это имеет наибольший смысл:

 const IMAGES = {
    bg1: require('<path-to-bg1>'),
    bg2: require('<path-to-bg2>'),
    ...
}
  

И затем в компоненте:

 const App = (props) => {
    return <div style={{backgroundImage: "url("   IMAGES[props.bgImg]   ")"}}>...</div>
}
  

Излишне говорить, что вам нужно обновить свои реквизиты, чтобы передавать ключ из IMAGES вместо путей к изображениям.

Комментарии:

1. 1 Спасибо Каве. Это работает. если я смогу понять, как webpack помещает файл после компиляции, и если я смогу ссылаться на них напрямую, тогда это будет более полезно

2. @upog Я добавил больше пояснений к началу ответа. Дайте мне знать, если это не имеет смысла! 🙂

3. да, когда я выполнял отладку в консоли разработчика, я обнаружил, /static/media/plot1.838f8b53.jpg и я не знаю, как сопоставить и опубликовал вопрос. Спасибо за ваше объяснение

4. просто чтобы добавить некоторую информацию, в css/scss если вы попытаетесь загрузить изображение, тогда оно также будет работать нормально background-image: url(../../../assets/plot1.jpg);

5. я думаю, что могу удалить .[hash:8] в wepack и использовать /static/media/ в качестве базового пути для своего изображения. но не уверен в последствиях