Reexport management example (#41)

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* Automated pre-commit update

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Co-authored-by: kopekC <28070492+kopekC@users.noreply.github.com>

Author: kopekC

examples/reexport_management/README.md

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+# Transform Module Re-exports Organization
+
+This example demonstrates how to use Codegen to automatically analyze and reorganize TypeScript module re-exports through shared directories. The script makes this process simple by handling all the tedious manual updates automatically.
+
+> [!NOTE]
+> This codemod helps maintain clean module boundaries and improves code organization by centralizing shared exports.
+
+## How the Migration Script Works
+
+The script automates the entire reorganization process in a few key steps:
+
+1. **Export Analysis**
+   ```python
+   for export_stmt in file.export_statements:
+       for export in export_stmt.exports:
+           if export.is_reexport() and not export.is_external_export:
+               all_reexports.append(export)
+   ```
+   - Automatically identifies re-exports in shared directories
+   - Analyzes export patterns and dependencies
+   - Uses Codegen's intelligent code analysis engine
+
+2. **Shared File Management**
+   ```python
+   resolved_public_file = export.resolved_symbol.filepath.replace("src/", "src/shared/")
+   if not codebase.has_file(resolved_public_file):
+       target_file = codebase.create_file(resolved_public_file, sync=True)
+   ```
+   - Creates or updates shared export files
+   - Maintains proper file structure
+   - Handles path resolution automatically
+
+3. **Import Updates**
+   ```python
+   # Updates imports to use new shared paths
+   new_path = usage.file.ts_config.translate_import_path(resolved_public_file)
+   new_import = f'import {{ {name} }} from "{new_path}"'
+   ```
+   - Updates all import statements to use new paths
+   - Maintains proper TypeScript path resolution
+   - Handles different import types (normal, type)
+
+## Why This Makes Organization Easy
+
+1. **Zero Manual Updates**
+   - Codegen SDK handles all file creation and updates
+   - No tedious export management
+
+2. **Consistent Structure**
+   - Ensures all shared exports follow the same pattern
+   - Maintains clean module boundaries
+
+3. **Safe Transformations**
+   - Validates changes before applying them
+   - Preserves existing functionality
+
+## Common Re-export Patterns
+
+### Module to Shared Exports
+```typescript
+// Before: Direct module import
+import { validateEmail } from '../module_a/src/functions';
+
+// After: Import through shared
+import { validateEmail } from '../module_a/src/shared';
+```
+
+### Export Consolidation
+```typescript
+// Before: Multiple export files
+export { foo } from './foo';
+export { bar } from './bar';
+
+// After: Consolidated in shared
+export * from '../functions';
+```
+
+## Key Benefits to Note
+
+1. **Better Module Boundaries**
+   - Clear public API for each module
+   - Centralized shared functionality
+
+2. **Improved Maintainability**
+   - Easier to track dependencies
+   - Simplified import paths
+
+3. **Code Organization**
+   - Consistent export structure
+   - Reduced import complexity
+
+
+The script will:
+1. 🎯 Start the reexport organization
+2. 📁 Analyze shared directories
+3. 🔄 Process and update exports
+4. ✨ Create shared export files
+5. 🧹 Clean up redundant exports
+
+## Learn More
+
+- [TypeScript Modules](https://www.typescriptlang.org/docs/handbook/modules.html)
+- [Export/Import Documentation](https://www.typescriptlang.org/docs/handbook/modules.html#export)
+- [Codegen Documentation](https://docs.codegen.com)
+- [Tutorial on Analyzing and Organizing Re-exports](https://docs.codegen.com/tutorials/managing-typescript-exports)
+- [More on exports ](https://docs.codegen.com/building-with-codegen/exports)
+## Contributing
+
+Feel free to submit issues and enhancement requests! 

examples/reexport_management/input_repo/modules/module_a/src/functions.ts

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+export const calculateSum = (a: number, b: number): number => {
+    return a + b;
+};
+
+export const formatName = (firstName: string, lastName: string): string => {
+    return `${firstName} ${lastName}`;
+};
+
+export const generateId = (): string => {
+    return Math.random().toString(36).substring(7);
+};
+
+export const validateEmail = (email: string): boolean => {
+    const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
+    return emailRegex.test(email);
+};
+
+export const capitalize = (str: string): string => {
+    return str.charAt(0).toUpperCase() + str.slice(1).toLowerCase();
+};

examples/reexport_management/input_repo/modules/module_a/src/shared/index.ts

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+export { calculateSum, formatName, capitalize } from '../module_a/src/functions';
+export { validateEmail } from '../module_c/src/shared/symbols/exports';
+

examples/reexport_management/input_repo/modules/module_b/imports.ts

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+import { calculateSum, formatName, capitalize, validateEmail } from './shared/exports';
+
+export const calculateAverage = (numbers: number[]): number => {
+    const sum = numbers.reduce((acc, curr) => calculateSum(acc, curr), 0);
+    return sum / numbers.length;
+};
+
+export const createUserProfile = (firstName: string, lastName: string): string => {
+    const formattedName = formatName(firstName, lastName);
+    return `Profile: ${formattedName}`;
+};
+
+export const formatText = (text: string): string => {
+    return text.split(' ').map(capitalize).join(' ');
+};
+
+export const multiply = (a: number, b: number): number => {
+    return a * b;
+};
+
+export const generateGreeting = (name: string): string => {
+    const email = validateEmail(name);
+    return `Hello, ${capitalize(name)}!`;
+};

examples/reexport_management/input_repo/modules/module_b/src/functions.ts

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+export { calculateSum, formatName, capitalize } from "../../imports";
+export {validateEmail} from "../../imports"

examples/reexport_management/input_repo/modules/module_b/src/shared/exports.ts

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+export { validateEmail, generateId } from '../module_a/src/functions';
+export { calculateAverage, multiply, createUserProfile } from '../module_b/src/functions';
+

examples/reexport_management/input_repo/modules/module_c/imports.ts

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+import { validateEmail, generateId, calculateAverage, multiply, createUserProfile } from './shared/symbols/exports';
+
+export const createUser = (email: string, firstName: string, lastName: string) => {
+    if (!validateEmail(email)) {
+        throw new Error('Invalid email');
+    }
+    
+    return {
+        id: generateId(),
+        profile: createUserProfile(firstName, lastName),
+        email
+    };
+};
+
+export const calculateMetrics = (values: number[]): { average: number; scaled: number[] } => {
+    const avg = calculateAverage(values);
+    const scaled = values.map(v => multiply(v, 2));
+    return { average: avg, scaled };
+};
+
+export const validateAndFormatUser = (email: string, firstName: string, lastName: string) => {
+    if (!validateEmail(email)) {
+        return { success: false, message: 'Invalid email' };
+    }
+    
+    const profile = createUserProfile(firstName, lastName);
+    return { success: true, profile };
+};
+
+export const processNumbers = (numbers: number[]): number => {
+    const { average } = calculateMetrics(numbers);
+    return multiply(average, 100);
+};
+
+export const generateReport = (userData: { email: string; name: string }): string => {
+    const isValidEmail = validateEmail(userData.email);
+    const id = generateId();
+    return `Report ${id}: Email ${isValidEmail ? 'valid' : 'invalid'} - ${userData.name}`;
+};

examples/reexport_management/input_repo/modules/module_c/src/functions.ts

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+export { validateEmail, generateId } from '../../../imports'
+export { calculateAverage, multiply, createUserProfile } from '../../../imports'

examples/reexport_management/input_repo/modules/module_c/src/shared/symbols/exports.ts

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+{
+  "name": "default-exports-test",
+  "version": "1.0.0",
+  "description": "Test codebase for converting default exports",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "devDependencies": {
+    "typescript": "^5.0.0"
+  }
+}

examples/reexport_management/input_repo/package.json

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+{
+  "compilerOptions": {
+    "baseUrl": "./",
+    "paths": {
+      "*": ["modules/*"]
+    }
+  },
+  "include": ["modules/**/*"]
+} 

examples/reexport_management/input_repo/tsconfig.json

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+import codegen
+from codegen import Codebase
+from codegen.sdk.typescript.file import TSImport
+from codegen.sdk.enums import ProgrammingLanguage
+
+processed_imports = set()
+@codegen.function("reexport_management")
+def run(codebase: Codebase):
+    print("🚀 Starting reexport analysis...")
+    for file in codebase.files:
+        # Only process files under /src/shared
+        if "examples/analize_reexports" not in file.filepath or '/src/shared' not in file.filepath:
+            continue
+        
+        print(f"📁 Analyzing: {file.filepath}")
+        
+        # Gather all reexports that are not external exports
+        all_reexports = []
+        for export_stmt in file.export_statements:
+            for export in export_stmt.exports:
+                if export.is_reexport() and not export.is_external_export:
+                    all_reexports.append(export)
+
+        if not all_reexports:
+            continue
+
+        print(f"📦 Found {len(all_reexports)} reexports to process")
+
+        for export in all_reexports:
+            has_wildcard = False
+
+            # Replace "src/" with "src/shared/"
+            resolved_public_file = export.resolved_symbol.filepath.replace("src/", "src/shared/")
+            print(f"🔄 Processing: {export.name} -> {resolved_public_file}")
+
+            # Get relative path from the "public" file back to the original file
+            relative_path = codebase.get_relative_path(
+                from_file=resolved_public_file,
+                to_file=export.resolved_symbol.filepath
+            )
+
+            # Ensure the "public" file exists
+            if not codebase.has_file(resolved_public_file):
+                print(f"✨ Creating new public file: {resolved_public_file}")
+                target_file = codebase.create_file(resolved_public_file, sync=True)
+            else:
+                target_file = codebase.get_file(resolved_public_file)
+
+            # If target file already has a wildcard export for this relative path, skip
+            if target_file.has_export_statement_for_path(relative_path, "WILDCARD"):
+                has_wildcard = True
+                continue
+
+            # Compare "public" path to the local file's export.filepath
+            if codebase._remove_extension(resolved_public_file) != codebase._remove_extension(export.filepath):
+                # A) Wildcard export
+                if export.is_wildcard_export():
+                    target_file.insert_before(f'export * from "{relative_path}"')
+                    print(f"⭐ Added wildcard export for {relative_path}")
+
+                # B) Type export
+                elif export.is_type_export():
+                    statement = file.get_export_statement_for_path(relative_path, "TYPE")
+                    if statement:
+                        if export.is_aliased():
+                            statement.insert(0, f"{export.resolved_symbol.name} as {export.name}")
+                        else:
+                            statement.insert(0, f"{export.name}")
+                        print(f"📝 Updated existing type export for {export.name}")
+                    else:
+                        if export.is_aliased():
+                            target_file.insert_before(
+                                f'export type {{ {export.resolved_symbol.name} as {export.name} }} '
+                                f'from "{relative_path}"'
+                            )
+                        else:
+                            target_file.insert_before(
+                                f'export type {{ {export.name} }} from "{relative_path}"'
+                            )
+                        print(f"✨ Added new type export for {export.name}")
+
+                # C) Normal export
+                else:
+                    statement = file.get_export_statement_for_path(relative_path, "EXPORT")
+                    if statement:
+                        if export.is_aliased():
+                            statement.insert(0, f"{export.resolved_symbol.name} as {export.name}")
+                        else:
+                            statement.insert(0, f"{export.name}")
+                        print(f"📝 Updated existing export for {export.name}")
+                    else:
+                        if export.is_aliased():
+                            target_file.insert_before(
+                                f'export {{ {export.resolved_symbol.name} as {export.name} }} '
+                                f'from "{relative_path}"'
+                            )
+                        else:
+                            target_file.insert_before(
+                                f'export {{ {export.name} }} from "{relative_path}"'
+                            )
+                        print(f"✨ Added new export for {export.name}")
+
+            # Update import usages
+            for usage in export.symbol_usages():
+                if isinstance(usage, TSImport) and usage not in processed_imports:
+                    processed_imports.add(usage)
+
+                    new_path = usage.file.ts_config.translate_import_path(resolved_public_file)
+
+                    if has_wildcard and export.name != export.resolved_symbol.name:
+                        name = f"{export.resolved_symbol.name} as {export.name}"
+                    else:
+                        name = usage.name
+
+                    if usage.is_type_import():
+                        new_import = f'import type {{ {name} }} from "{new_path}"'
+                    else:
+                        new_import = f'import {{ {name} }} from "{new_path}"'
+
+                    usage.file.insert_before(new_import)
+                    usage.remove()
+                    print(f"🔄 Updated import in {usage.file.filepath}")
+
+            # Remove old export
+            export.remove()
+            print(f"🗑️  Removed old export from {export.filepath}")
+
+        # Clean up empty files
+        if not file.export_statements and len(file.symbols) == 0:
+            file.remove()
+            print(f"🧹 Removed empty file: {file.filepath}")
+        codebase.commit()
+
+if __name__ == "__main__":
+    print("🎯 Starting reexport organization...")
+    codebase = Codebase("./", programming_language=ProgrammingLanguage.TYPESCRIPT)
+    run(codebase)
+    print("✅ Done! All reexports organized successfully!")