{"record":{"id":"0e649ff116019e92","repo":"angular/angular-cli","slug":"prebundling-has-been-configured-but-will-not-be-us","errorCode":null,"errorMessage":"Prebundling has been configured but will not be used because it is not supported by the \"${builderName}\" builder.","messagePattern":"Prebundling has been configured but will not be used because it is not supported by the \"(.+?)\" builder\\.","errorType":"console","errorClass":null,"httpStatus":null,"severity":"warning","filePath":"packages/angular_devkit/build_angular/src/builders/dev-server/builder.ts","lineNumber":126,"sourceCode":"              (options, context, codePlugins) => {\n                return builderName === '@angular-devkit/build-angular:browser-esbuild'\n                  ? // eslint-disable-next-line @typescript-eslint/no-explicit-any\n                    buildApplicationInternal(convertBrowserOptions(options as any), context, {\n                      codePlugins,\n                    })\n                  : buildApplicationInternal(options, context, { codePlugins });\n              },\n              context,\n              transforms,\n              extensions,\n            ),\n          ),\n        );\n      }\n\n      // Warn if the initial options provided by the user enable prebundling with Webpack-based builders\n      if (options.prebundle) {\n        context.logger.warn(\n          `Prebundling has been configured but will not be used because it is not supported by the \"${builderName}\" builder.`,\n        );\n      }\n\n      if (extensions?.buildPlugins?.length) {\n        throw new Error('Only the \"application\" and \"browser-esbuild\" builders support plugins.');\n      }\n      if (extensions?.middleware?.length) {\n        throw new Error(\n          'Only the \"application\" and \"browser-esbuild\" builders support middleware.',\n        );\n      }\n\n      // Webpack based build systems default to false for hmr option\n      normalizedOptions.hmr ??= false;\n\n      // Use Webpack for all other browser targets\n      return defer(() => import('./webpack-server')).pipe(","sourceCodeStart":108,"sourceCodeEnd":144,"githubUrl":"https://github.com/angular/angular-cli/blob/bb72145f9ab45aee29f523236b3a25cd0813a841/packages/angular_devkit/build_angular/src/builders/dev-server/builder.ts#L108-L144","documentation":"Warning that esbuild prebundling (the 'prebundle' option, backed by Vite-style dependency prebundling) is enabled but the resolved underlying builder is Webpack-based, which does not support prebundling. The option is ignored and rebuild/startup speed benefits are lost.","triggerScenarios":"Setting `prebundle: true` (or the default truthy value) on the dev-server target while builderName resolves to a Webpack builder (legacy 'browser' + 'dev-server' combo).","commonSituations":"Projects that enabled prebundle in a serve config shared between esbuild and Webpack targets; partial migrations where the app builder was swapped but the dev-server target options kept `prebundle`.","solutions":["Remove the `prebundle` option from the serve target.","Migrate the application builder to '@angular/build:application' so prebundling is actually supported.","Or keep the option only in configurations used by esbuild-based builders."],"exampleFix":"// before\n\"options\": { \"prebundle\": true }\n// after (webpack-based serve)\n\"options\": {}","handlingStrategy":"validation","validationCode":"if (builderName.startsWith('@angular-devkit') && target.options?.prebundle) {\n  console.warn('prebundle ignored: requires an esbuild-based application builder.');\n}","typeGuard":"function enablesPrebundle(o: unknown): o is { prebundle: boolean } {\n  return typeof o === 'object' && o !== null && (o as any).prebundle === true;\n}","tryCatchPattern":null,"preventionTips":["Only set prebundle on targets whose application builder is esbuild-based.","Verify startup speed improvements actually materialize after enabling prebundling.","Keep dev-server and application builder families consistent."],"tags":["angular-cli","dev-server","prebundling","build-options"],"backgroundTag":"unsupported-builder-option","analyzedSha":"bb72145f9ab45aee29f523236b3a25cd0813a841","analyzedAt":"2026-08-30T02:47:34.745Z","schemaVersion":2},"datasetVersion":"2026-08-30T03:17:51.788Z"}