# Codemod Reference — Automated Migration Tool

> Automated codemod to migrate from Vite import.meta.env, CRA process.env.REACT_APP_*, and Next.js NEXT_PUBLIC_* to REP runtime environment variables. Idempotent and non-destructive.

Source: https://rep-protocol.dev/reference/codemod/

```bash
npm install -D @rep-protocol/codemod
# or
npx @rep-protocol/codemod [options] [files...]
```

## Usage

```bash
rep-codemod [options] [files or directories...]
```

## Options

| Flag | Default | Description |
|---|---|---|
| `-f, --framework <name>` | `vite` | Framework preset: `vite`, `cra`, `next` |
| `--dry-run` | `false` | Preview changes without writing files |
| `--extensions <list>` | `ts,tsx,js,jsx` | Comma-separated file extensions to process |

## Framework presets

### `--framework vite`

Transforms `import.meta.env.VITE_*` to `rep.get('*')`:

```typescript
// Before
const apiUrl = import.meta.env.VITE_API_URL;

// After
import { rep } from '@rep-protocol/sdk';
const apiUrl = rep.get('API_URL');
```

Vite built-ins (`MODE`, `DEV`, `PROD`, `SSR`, `BASE_URL`) are left untouched.

### `--framework cra`

Transforms `process.env.REACT_APP_*` to `rep.get('*')`:

```typescript
// Before
const apiUrl = process.env.REACT_APP_API_URL;

// After
import { rep } from '@rep-protocol/sdk';
const apiUrl = rep.get('API_URL');
```

### `--framework next`

Transforms `process.env.NEXT_PUBLIC_*` to `rep.get('*')`:

```typescript
// Before
const apiUrl = process.env.NEXT_PUBLIC_API_URL;

// After
import { rep } from '@rep-protocol/sdk';
const apiUrl = rep.get('API_URL');
```

## Examples

```bash
# Transform Vite project
rep-codemod --framework vite src/

# Dry run — preview changes
rep-codemod --framework cra --dry-run src/components/

# Specific files
rep-codemod --framework next src/app/page.tsx src/lib/api.ts

# JavaScript files only
rep-codemod --framework vite --extensions js,jsx src/
```

## Behavior

- **Idempotent** — running twice produces the same result
- **Import management** — adds `import { rep } from '@rep-protocol/sdk'` if absent
- **Non-destructive** — only prefixed variables are transformed
- **Format-preserving** — original formatting and comments are preserved (via jscodeshift/recast)

## Post-migration steps

1. Remove framework-specific type augmentations (e.g., `vite-env.d.ts`)
2. Run `rep typegen` to generate typed overloads
3. Update container config to set `REP_PUBLIC_*` environment variables