feat: Add unified fluentui-react-native mono-package with subpath exports and migration codemod

[Saadnajmi]

Summary

Introduces a new unified mono-package (fluentui-react-native) that re-exports every publishable package in the monorepo via subpath exports. Consumers only need a single dependency and a single version number.

Also includes a jscodeshift codemod that automates migration of both source imports and package.json dependencies, and demonstrates the migration on tester-core (155 files).

Motivation

Today, consumers must track ~70 individual @fluentui-react-native/* packages with independent version numbers. This makes upgrades painful and package.json files unwieldy. A single fluentui-react-native package with subpath imports gives consumers one dependency to manage while preserving tree-shaking.

What's included

1. Mono-package (packages/libraries/fluentui-react-native/)

• 76 subpath exports (70 individual + 6 category barrels) — all resolve to TypeScript source files in src/
• No build step — exports point directly to .ts re-export files; consumers' bundlers (Metro, Webpack) compile them as part of the app build
• ESM-only ("type": "module", "sideEffects": false) for optimal tree-shaking
• Auto-generated — update-exports.mts discovers all publishable packages, generates src/ files, and updates package.json exports/dependencies
• CI-enforced — check-exports task in lage buildci fails if any publishable package is missing

Usage:

// Individual subpaths (recommended — one package per import)
import { Button } from 'fluentui-react-native/button';
import { ThemeProvider } from 'fluentui-react-native/theme';

// Category barrels (convenience — all packages in a group)
import { Button, Avatar } from 'fluentui-react-native/components';
import { ThemeProvider } from 'fluentui-react-native/core';

2. Migration codemod (packages/codemods/)

A jscodeshift transform + package.json migration tool:

• Source migration: rewrites @fluentui-react-native/*, @fluentui/react-native, and @uifabricshared/* imports to fluentui-react-native/<subpath>
• Barrel decomposition: expands import { Button, Theme } from '@fluentui/react-native' into per-symbol subpath imports
• package.json migration: removes individual scoped dependencies, adds single fluentui-react-native dependency
• Supports both import and require() syntax

yarn migrate-to-mono-package --path src/

3. tester-core migration (demonstration)

• Migrated 155 source files from individual @fluentui-react-native/* imports to fluentui-react-native/* subpaths
• Removed 61 individual dependencies from package.json, replaced with single fluentui-react-native
• Converted tester-core to ESM ("type": "module") since the mono-package is ESM-only

4. Build system changes

• lage.config.mjs: Added check-exports task to the buildci pipeline
• lintPackage.ts: Skip "." export validation for subpath-only packages; skip default entry enforcement when source file doesn't exist
• buildConfig.ts: Suppress CJS build for packages without a main field (not just type: module packages)
• End apps (fluent-tester, win32, win32-81): Use module: esnext / moduleResolution: bundler to support ESM tester-core dependency; removed unnecessary build-cjs

Design decisions

Decision	Rationale
Unscoped package name (fluentui-react-native)	Short imports: fluentui-react-native/button vs @fluentui-react-native/mono/button
Subpath exports only (no root barrel)	Prevents accidental import of everything; forces tree-shakeable imports
Source .ts exports (no lib/)	Standard for React Native packages; avoids build step; bundlers compile directly
Category barrels with @ts-nocheck	Aggregating overlapping packages causes TS2308 duplicate export errors; individual subpaths are unaffected
Auto-generation script	Single source of truth; CI prevents drift; adding a new package only requires running yarn update-exports

Testing

• yarn lage buildci passes (build, lint, format, depcheck, lint-package, check-exports, check-publishing)
• tester-core builds and type-checks with migrated imports
• update-exports.mts --check validates all src/ files and package.json fields

Migration guide

Existing consumers can migrate incrementally:

1. yarn add fluentui-react-native
2. Run the codemod: yarn migrate-to-mono-package --path src/
3. Verify the build

The individual @fluentui-react-native/* packages continue to be published — this is additive, not breaking.

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