feat(config): support .config/ directory and YAML/TOML formats via unjs/c12

[okikio]

Adds support for the .config/ directory convention and expands config format support by replacing the manual config discovery/loading system with unjs/c12.

Summary

Config discovery now searches .config/ directory. Repomix finds config files in this order:

1. Explicit --config path (if provided)
2. Project root: repomix.config.{ext}
3. .config/ directory: .config/repomix.{ext} or .config/repomix.config.{ext}
4. Global config directory (fallback)

YAML and TOML formats are now supported alongside the existing TypeScript, JavaScript, and JSON/JSONC/JSON5 formats.

repomix --init is now interactive. Users choose where to place the config file:

• Project root (repomix.config.json)
• .config/ directory (config/repomix.json)
• .config/ directory with full name (.config/repomix.config.json)

Dependency changes:

• Added c12 — handles config file discovery, loading, and format parsing
• Removed json5 — c12 uses confbox internally for JSON5/JSONC/YAML/TOML
• Removed jiti — c12 declares it as an optional peer dep and imports it dynamically

Why c12

c12 is the config loader behind Nuxt and the unjs ecosystem. It handles the hard parts, file discovery across directories, dynamic TS/JS loading via jiti, and multi-format parsing via confbox, while giving control over merge policy, validation, and trust boundaries. This replaces ~100 lines of manual file-existence checks and format-specific loading with a single well-tested dependency. Plus, my primary reason for adding it, is it enables support for project-level .config/ directories, I thought it would be kinda nice.

Scope

This PR focuses on .config/ directory support and the format expansion that comes with c12. Several c12 features are explicitly disabled for now:

• rcFile (.repomixrc) — deferred
• packageJson (repomix key in package.json) — deferred
• extend (config inheritance) — deferred
• globalRc, envName, dotenv — deferred

Note

I didn't want to go to far ahead so I limited the change to only adding the .config/ directory support, but you might actually want to enable some of the other powerful features unjs/c12 supports.

This pr doesn't change the merge logic (mergeConfigs) because c12's defu merges arrays in reversed order, which doesn't match existing behavior, and I was weary of making too many changes in one pr.

Warning

A slight side-effect change that shouldn't cause any bugs but it is worth keeping in mind, is that by default the preference order for files is slightly tweaked, so unlike before where if the end user had both a repomix.config.js and repomix.config.ts it would prefer the .ts, with c12 it by default prefers the .ts version of the config.

This is mostly a rare occurrence but it can happen so it's worth being aware.

Files changed

Core:

• configLoad.ts — Rewrote discovery/loading to use c12; merge logic unchanged
• initAction.ts — Added interactive config location prompt (given that .config/ is now available as a location I thought it best to add an interactive selection menu for determining where to place the repomix.config.ts)
• cliRun.ts — Updated CLI help text
• package.json — Dependency changes (c12 added, json5/jiti removed; c12 already uses jiti under the hood)

Tests:

• configLoad.test.ts — Rewrote loadFileConfig tests to mock c12Load via DI; added config priority ordering tests
• configLoad.integration.test.ts — Updated DI for dynamic config tests
• initAction.test.ts — Added .config/ directory tests, fixed mocks for new interactive prompt

Docs (README + english language website docs):

• Updated config format lists to include YAML/TOML
• Added .config/ directory to search locations
• Updated --init and --config descriptions
• Updated Configuration File Locations sections

Note

A separate pr might be necessary to update all the other languages.

Checklist

• Run npm run test
• Run npm run lint

Closes #1365

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📝 Walkthrough

Walkthrough

This PR transitions Repomix config handling to support interactive initialization with multiple locations and formats. It replaces custom discovery logic with c12 library integration, enabling config file detection in project root and .config/ directories across JSON, TypeScript, JavaScript, YAML, and TOML formats.

Changes

Cohort / File(s)	Summary
Dependencies & Library Migration package.json	Removed jiti and json5; added c12 (^4.0.0-beta.4) to support multi-format config discovery.
Config Loading Refactor src/config/configLoad.ts	Replaced bespoke config discovery and file-format handling with c12-based loading. Introduced loadConfigFromC12 and validateConfig helpers; updated --config resolution and local/global discovery to delegate to c12.loadConfig; adjusted error handling for new library behavior.
Config Initialization src/cli/actions/initAction.ts	Added interactive prompts.select for config location selection (project root vs .config/ directory); replaced hardcoded repomix.config.json messaging with dynamic configFileName derived from user choice; consolidated config path resolution logic.
CLI Help Text src/cli/cliRun.ts, README.md	Updated help text for --config to document support for multiple formats (.json, .ts, .js, .yaml, .toml); updated --init to describe interactive config creation with location/format selection.
Configuration Documentation website/client/src/en/guide/command-line-options.md, website/client/src/en/guide/configuration.md, website/client/src/en/index.md	Updated CLI options documentation and configuration guide to reflect multi-format support, interactive --init flow, and consolidated search order (explicit path, project root, .config/, global directory fallback).
Test Updates tests/cli/actions/initAction.test.ts, tests/config/configLoad.test.ts, tests/config/configLoad.integration.test.ts	Added prompts.select mocking for location selection; expanded cancellation coverage; refactored config loading tests from fs-based behavior to c12Load injection; added precedence and discovery assertion tests.

Sequence Diagram

sequenceDiagram
    actor User
    participant CLI Init
    participant Prompts
    participant Config System
    participant c12 Discovery

    User->>CLI Init: Run `repomix --init`
    CLI Init->>Prompts: Show location options
    Prompts->>User: Select root or .config/
    User->>Prompts: Choose location & format
    Prompts->>CLI Init: Return selection
    CLI Init->>Config System: createConfigFile(location, format)
    Config System->>Config System: Resolve configPath & configFileName
    Config System->>User: Prompt for overwrite (if exists)
    User->>Config System: Confirm/skip
    Config System->>Config System: Write config file
    
    Note over User,Config System: Later: Normal config load flow
    User->>CLI Init: Run repomix (load config)
    CLI Init->>Config System: loadFileConfig()
    Config System->>c12 Discovery: Search locations in order
    c12 Discovery->>c12 Discovery: Check --config path
    c12 Discovery->>c12 Discovery: Check project root
    c12 Discovery->>c12 Discovery: Check .config/ directory
    c12 Discovery->>c12 Discovery: Check global directory
    c12 Discovery->>Config System: Return matched file + parsed config
    Config System->>CLI Init: Resolved configuration

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Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Possibly related PRs

• feat(config): Add support for .jsonc extension with priority order #620: Modifies config discovery and file priority handling in configLoad.ts
• feat: Add support for JSON5 in configuration files #366: Adds JSON5 parsing to config loading, prior to c12 migration
• refactor(actions): conditional assignments #147: Changes config path determination and cancellation logic in initAction.ts

Suggested reviewers

• yamadashy

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately and specifically describes the main changes: adding .config/ directory support and expanding config formats (YAML/TOML) via the c12 dependency.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Description check	✅ Passed	The PR description is comprehensive and well-structured, covering the changes, rationale, dependency updates, scope, and files affected with detailed explanations.

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