angular/angular-cli · error · Error

Unknown error occurred processing bundle for "${path}".

Error message

Unknown error occurred processing bundle for "${path}".

What it means

During the esbuild-based bundling of an Angular application, the transform result for a bundle (e.g. a chunk or locale data file) came back null/undefined or with no code. The devkit treats this as an unrecoverable, unexpected failure of the bundler rather than a user-facing build error, so it throws this generic message. It almost always indicates the esbuild transform pipeline itself failed silently (native binary mismatch, crash, or resource issue) rather than a problem in your source code.

Source

Thrown at packages/angular_devkit/build_angular/src/utils/process-bundle.ts:399

    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    inputSourceMap: false as any,
    babelrc: false,
    configFile: false,
    presets: [
      [
        require.resolve('@babel/preset-env'),
        {
          targets: { esmodules: true },
        },
      ],
    ],
    minified: allowMinify && optimize,
    compact: !shouldBeautify && optimize,
    comments: !optimize,
  });

  if (!transformResult || !transformResult.code) {
    throw new Error(`Unknown error occurred processing bundle for "${path}".`);
  }

  return transformResult.code;
}

View on GitHub (pinned to bb72145f9a)

Solutions

1. Delete node_modules and lockfile, reinstall (npm ci) so the correct @esbuild/<platform> binary is installed
2. Clear the Angular CLI cache (rm -rf .angular/cache)
3. Verify your Node version is in the supported range for your @angular-devkit/build_angular version and upgrade @angular-devkit/build_angular
4. If building in Docker, ensure the build stage runs on the same platform as the installed esbuild binary; avoid copying node_modules across platforms

Example fix

# before (broken install)
node_modules/@esbuild/linux-x64/bin/esbuild  # missing or wrong arch
# after
rm -rf node_modules package-lock.json
npm install

import { existsSync } from 'fs';
const esbuildBin = require.resolve('esbuild');
if (!existsSync(esbuildBin)) throw new Error('esbuild missing; reinstall node_modules');
// Also verify the platform binary:
try { require('@esbuild/linux-x64'); } catch { throw new Error('Platform esbuild binary missing; run npm ci'); }

function hasCode(r: { code?: string } | null | undefined): r is { code: string } {
  return !!r && typeof r.code === 'string' && r.code.length > 0;
}

try {
  await build(options);
} catch (e) {
  if (e instanceof Error && e.message.includes('Unknown error occurred processing bundle')) {
    // reinstall node_modules, clear .angular/cache, retry once
  }
  throw e;
}

When it happens

Trigger: loadLocaleData/inlineLocales call process-bundle's transform path and esbuild's transform returns an empty result: corrupted or platform-mismatched esbuild native binary, esbuild crashing (OOM, unsupported platform), or a transform invoked with options that produce no output.

Common situations: Corrupted node_modules after switching Node versions or platforms (e.g. Docker image built on different arch), running out of memory during large builds, npm/yarn optional-dependency install bugs that skip the platform-specific @esbuild/* binary, stale Angular CLI cache.

Related errors

• esbuild implementation missing
• The 'vendorChunk' option is not used by this builder and wil
• The 'commonChunk' option is always enabled by this builder a
• The 'webWorkerTsConfig' option is not yet supported by this
• Could not find ${level} workspace.

AI-assisted analysis of angular/angular-cli@bb72145f9a (2026-08-30). Data as JSON: /api/errors/fd278e956ace96f4. Report an issue: GitHub.