feat(formatter): support custom internal import patterns

[relsunkaev]

Summary

• honor .oxfmtrc experimentalSortImports.internalPattern by parsing prefixes once in the formatter core, validating config input, and surfacing the option through the NAPI playground + schema docs
• add Vitest write-mode coverage (with a RegExp.escape polyfill) so the CLI path stays exercised end to end when internal prefixes or literal asterisks are configured

Testing

• pnpm --filter oxfmt-app run build-test
• pnpm --filter oxfmt-app test

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[Copilot]

Pull request overview

This pull request adds support for custom internal import patterns in the formatter's experimental import sorting feature. It allows users to configure patterns (e.g., "@company/", "pkg-") via .oxfmtrc's experimentalSortImports.internalPattern field to classify imports as "internal" when sorting. The implementation includes configuration validation, NAPI playground integration, and comprehensive end-to-end tests.

Key changes:

• Added internalPattern configuration option accepting single string or array of strings in JSON schema and config files
• Implemented prefix-based pattern matching with optional trailing * support (e.g., @acme/* becomes @acme/ prefix matcher)
• Added ES2025 RegExp.escape polyfill for test utilities to handle special characters in path normalization

Reviewed changes

Copilot reviewed 16 out of 17 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
npm/oxfmt/configuration_schema.json	Added internalPattern and StringOrStringArray schema definitions for import sorting configuration
napi/playground/src/options.rs	Added internal_pattern field to OxcSortImportsOptions accepting string or array of strings
napi/playground/src/lib.rs	Implemented conversion logic from NAPI options to internal patterns with error handling
napi/playground/index.d.ts	Added TypeScript type definition for internalPattern option
crates/oxc_formatter/tests/snapshots/schema_json.snap	Updated snapshot with new schema definitions
crates/oxc_formatter/src/service/oxfmtrc.rs	Added deserialization, validation, and normalization for internalPattern config with comprehensive tests
crates/oxc_formatter/src/options.rs	Implemented InternalImportPattern struct with prefix-based matching logic and unit tests
crates/oxc_formatter/src/lib.rs	Exported normalize_internal_pattern_value for NAPI integration
crates/oxc_formatter/src/ir_transform/sort_imports/compute_metadata.rs	Integrated internal pattern matching into import path classification logic
crates/oxc_formatter/examples/sort_imports.rs	Updated example to initialize new internal_patterns field
apps/oxfmt/test/utils.ts	Added RegExp.escape polyfill for ES2025 compatibility in path normalization
apps/oxfmt/test/sort_imports_internal_pattern.test.ts	Added end-to-end tests for internal pattern configuration
apps/oxfmt/test/fixtures/sort_imports_internal_pattern/*	Added test fixtures for monorepo patterns and literal asterisk handling
apps/oxfmt/test/__snapshots__/sort_imports_internal_pattern.test.ts.snap	Added snapshots verifying correct import sorting with internal patterns

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[relsunkaev]

@copilot These fixture files are intentional inputs for the write-mode snapshot tests—the imports are the actual content we run through oxfmt, so they are expected to be unused in the fixture itself.

[relsunkaev]

@copilot Clarified how the trailing works per your suggestion. Thanks!

[nnnnoel]

I think it's duplicate with #16372

[leaysgur]

Oops, thanks for the PR and for your interest in the project!

Unfortunately, I've already been working on this same feature myself, so I won't be able to merge this... Sorry for the overlap! 🙏🏻

For next time, feel free to open or comment an issue first — that way we can check if something's already in progress and avoid stepping on each other's toes.

I appreciate the effort, and hope to see you around the project again!

[relsunkaev]

All good! Just glad this is getting implemented