# transformSync()

macroforge v0.1.48

Synchronously transforms TypeScript code through the macro expansion system.
This is similar to \[\`expand\_sync\`\] but returns a \[\`TransformResult\`\]
which includes source map information (when available).

## Signature

TypeScript

```
function transformSync(
  code: string,
  filepath: string
): TransformResult
```

## Parameters

| Parameter  | Type     | Description                          |
| ---------- | -------- | ------------------------------------ |
| `code`     | `string` | TypeScript source code to transform  |
| `filepath` | `string` | File path (used for error reporting) |

## TransformResult

TypeScript

```
interface TransformResult {
  // Transformed TypeScript code
  code: string;

  // Source map (JSON string, not yet implemented)
  map?: string;

  // Generated type declarations
  types?: string;

  // Macro expansion metadata
  metadata?: string;
}
```

## Comparison with expandSync()

| Feature        | `expandSync`    | `transformSync` |
| -------------- | --------------- | --------------- |
| Options        | Yes             | No              |
| Diagnostics    | Yes             | No              |
| Source Mapping | Yes             | Limited         |
| Use Case       | General purpose | Build tools     |

## Example

TypeScript

```
import { transformSync } from "macroforge";

const sourceCode = \`
/** @derive(Debug) */
class User {
  name: string;
}
\`;

const result = transformSync(sourceCode, "user.ts");

console.log(result.code);

if (result.types) {
  // Write to .d.ts file
  fs.writeFileSync("user.d.ts", result.types);
}

if (result.metadata) {
  // Parse and use metadata
  const meta = JSON.parse(result.metadata);
  console.log("Macros expanded:", meta);
}
```

## When to Use

Use `transformSync` when:

- Building custom integrations
- You need raw output without diagnostics
- You're implementing a build tool plugin

Use `expandSync` for most other use cases, as it provides better error handling.