refactor(errors): use HttpProxyMiddlewareError class

[chimurai]

Summary by CodeRabbit

• Bug Fixes
  • Improved error reporting with consistent error codes for configuration failures (missing target, invalid path filters, invalid path rewrites)
  • Enhanced error messages for multipart form data validation

[coderabbitai]

Caution

Review failed

Pull request was closed or merged during review

📝 Walkthrough

Walkthrough

The ERRORS enum is removed from src/errors.ts. All four modules that previously threw generic errors using ERRORS constants (configuration.ts, path-filter.ts, path-rewriter.ts, stringify-form-data.ts) are updated to throw HttpProxyMiddlewareError with explicit messages and module-specific error code strings. Unit tests are updated to assert typed errors and specific codes.

Changes

Typed Error Migration

Layer / File(s)	Summary
Remove ERRORS enum and throw typed errors in source modules src/errors.ts, src/configuration.ts, src/path-filter.ts, src/path-rewriter.ts, src/handlers/fix-request-body-utils/stringify-form-data.ts	Deletes the ERRORS enum entirely. Each module replaces its ERRORS-based generic Error throw with HttpProxyMiddlewareError carrying a specific code: ERR_CONFIG_FACTORY_TARGET_MISSING, HPM_INVALID_PATH_FILTER_CONFIG, HPM_INVALID_PATH_FILTER_ARRAY_CONFIG, HPM_INVALID_PATH_REWRITER_CONFIG, and HPM_ERR_INVALID_MULTIPART_{BOUNDARY,FIELD_NAME,FIELD_VALUE}. HPM_ERR_INVALID_MULTIPART is now exported from stringify-form-data.ts.
Update unit tests to assert typed error codes test/unit/configuration.spec.ts, test/unit/path-filter.spec.ts, test/unit/path-rewriter.spec.ts	Imports HttpProxyMiddlewareError in each test file and updates error-throw assertions to verify both the error class and the specific code property value for each invalid-configuration scenario.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• chimurai/http-proxy-middleware#1197: Refactors isValidRewriteConfig typings and signatures in src/path-rewriter.ts, the same function where this PR changes the thrown error type to HttpProxyMiddlewareError with HPM_INVALID_PATH_REWRITER_CONFIG.

Poem

🐰 Hop, hop, no more generic throws!
Each error now a typed bunny that glows,
HttpProxyMiddlewareError in every lair,
With codes like HPM_INVALID to declare.
The ERRORS enum hops away for good —
Typed errors blooming just as they should! 🌸

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main refactoring objective: replacing generic error handling with the HttpProxyMiddlewareError class across multiple modules.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch refactor-errors

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[pkg-pr-new]

npm i https://pkg.pr.new/http-proxy-middleware@1264

commit: 97bcb6f

[coveralls]

coverage: 95.183% (-0.06%) from 95.238% — refactor-errors into master