# Javy + Wasmer Compatibility Analysis

## Summary

**✅ Static Build**: Javy's static build (`transform.wasm`) works perfectly with Wasmer CLI  
**❌ Dynamic Build**: Javy's dynamic build approach is not compatible with Wasmer CLI

## Test Results

### Static Build (Working)
```bash
# File: transform.wasm (1.3MB raw, 519KB gzipped)
echo '{"users":[{"name":"Alice","age":30}]}' | wasmer run transform.wasm
# ✅ Output: {"message":"Data has been processed by Javy WASM",...}
```

### Dynamic Build (Not Working)
```bash
# Files: plugin.wasm (1.2MB) + transform_dynamic.wasm (3.5KB)
echo '{"users":[{"name":"Alice","age":30}]}' | wasmer run transform_dynamic.wasm
# ❌ Error: unknown import "javy_quickjs_provider_v3"."canonical_abi_realloc"
```

## Technical Analysis

### Why Static Build Works
- **Self-contained**: All JavaScript engine code is embedded in the WASM binary
- **No imports**: Doesn't require external modules or dynamic linking
- **WASI compatible**: Uses standard WASI interfaces for I/O
- **Single file**: Wasmer can run it directly with `wasmer run transform.wasm`

### Why Dynamic Build Fails
- **Dynamic linking**: Requires importing functions from `javy_quickjs_provider_v3`
- **Multi-file**: Needs both plugin.wasm (engine) + transform_dynamic.wasm (code)
- **Wasmer limitation**: CLI doesn't support dynamic linking between WASM modules
- **Import resolution**: No mechanism to resolve imports from separate WASM files

## Wasmer CLI Limitations

The `wasmer run` command signature is:
```
wasmer run <INPUT> [ARGS]...
```

- Only accepts a **single WASM file** as input
- No built-in support for dynamic linking
- No `--plugin` or `--import-from` flags
- The `--use` flag is for containers, not WASM imports

## Alternative Approaches

### 1. Wasmer SDK Integration
The Wasmer SDK (Rust, Python, etc.) might support:
- Manual import resolution
- Loading multiple WASM modules
- Custom linking between modules

### 2. WASM Component Model
Future WASM standards may enable:
- Component composition
- Interface-based linking
- Multi-module applications

### 3. Bundle Approach
Create a bundled WASM that includes both:
- The Javy engine
- The JavaScript code
- Similar to static build but more flexible

## Size Comparison

| Approach       | Raw Size      | Gzipped      | Wasmer Compatible |
| -------------- | ------------- | ------------ | ----------------- |
| Static Build   | 1.3MB         | 519KB        | ✅ Yes             |
| Dynamic Build  | 1.2MB + 3.5KB | ~488KB + 2KB | ❌ No              |
| QuickJS (Rust) | 692KB         | 283KB        | ✅ Yes             |

## Recommendations

### For Wasmer CLI Usage
1. **Use Static Build**: `javy build -o transform.wasm transform.js`
   - Single file deployment
   - 519KB gzipped
   - Perfect Wasmer compatibility

2. **Consider QuickJS**: Alternative with smaller size (283KB gzipped)
   - Rust + QuickJS implementation
   - Also Wasmer compatible
   - More flexible for custom JavaScript engines

### For Production Deployment
- **Static builds** are ideal for Wasmer Edge, containers, and CLI usage
- **Dynamic builds** might work with Wasmer SDK but require custom integration
- **Size vs Flexibility**: Static builds are larger but simpler to deploy

## Conclusion

**Javy + Wasmer works best with static builds.** The dynamic plugin approach, while more efficient for multiple JavaScript functions, is not compatible with Wasmer CLI due to its lack of dynamic linking support.

For Wasmer integration, choose:
- **Javy Static**: 519KB, full JavaScript compatibility
- **QuickJS Rust**: 283KB, custom JavaScript engine
- Both provide excellent Wasmer compatibility for production use