Babel Preset

The Babel preset extends the AgentScript preset to enable secure TSX/JSX transformation inside the enclave. It adds the Babel global while maintaining all AgentScript security guarantees.

Overview

The Babel preset provides:

Babel.transform() - Transform TSX/JSX to JavaScript
Security configs - Per-level limits for input size, output size, timeouts
Preset whitelist - Only allowed Babel presets can be used
Full AgentScript validation - All blocked constructs remain blocked

Basic Usage

import { createBabelPreset, JSAstValidator } from '@enclave-vm/ast';

const validator = new JSAstValidator(createBabelPreset({
  securityLevel: 'STANDARD',
}));

const result = await validator.validate(`
  const tsx = '<div>Hello</div>';
  const js = Babel.transform(tsx, { presets: ['react'] });
  return js.code;
`);

Security Configurations

The Babel preset defines security limits per security level:

import { getBabelConfig, BABEL_SECURITY_CONFIGS } from '@enclave-vm/ast';

// Get config for a specific level
const config = getBabelConfig('SECURE');

// Or access all configs
console.log(BABEL_SECURITY_CONFIGS);

Configuration by Security Level

Level	Max Input	Max Output	Timeout	Allowed Presets
`STRICT`	100 KB	500 KB	5s	`react`
`SECURE`	500 KB	2 MB	10s	`typescript`, `react`
`STANDARD`	1 MB	5 MB	15s	`typescript`, `react`
`PERMISSIVE`	5 MB	25 MB	30s	`typescript`, `react`, `env`

Use STRICT for untrusted input where you only need JSX transformation. Use STANDARD for typical LLM-generated TypeScript+React code.

Configuration Options

interface BabelSecurityConfig {
  /** Maximum input code size in bytes */
  maxInputSize: number;

  /** Maximum output code size in bytes */
  maxOutputSize: number;

  /** Transform timeout in milliseconds */
  transformTimeout: number;

  /** Allowed Babel preset names */
  allowedPresets: string[];
}

Default Configurations

// STRICT - Minimal, JSX only
{
  maxInputSize: 100 * 1024,    // 100 KB
  maxOutputSize: 500 * 1024,   // 500 KB
  transformTimeout: 5000,       // 5 seconds
  allowedPresets: ['react'],
}

// SECURE - TypeScript + React
{
  maxInputSize: 500 * 1024,    // 500 KB
  maxOutputSize: 2 * 1024 * 1024, // 2 MB
  transformTimeout: 10000,      // 10 seconds
  allowedPresets: ['typescript', 'react'],
}

// STANDARD - Default for most use cases
{
  maxInputSize: 1024 * 1024,   // 1 MB
  maxOutputSize: 5 * 1024 * 1024, // 5 MB
  transformTimeout: 15000,      // 15 seconds
  allowedPresets: ['typescript', 'react'],
}

// PERMISSIVE - Extended capabilities
{
  maxInputSize: 5 * 1024 * 1024,   // 5 MB
  maxOutputSize: 25 * 1024 * 1024, // 25 MB
  transformTimeout: 30000,          // 30 seconds
  allowedPresets: ['typescript', 'react', 'env'],
}

Allowed Globals

The Babel preset adds these globals to the AgentScript allowlist:

Global	Description
`Babel`	The restricted Babel transform API
`__safe_Babel`	Internal transformed version

All other AgentScript allowed globals remain available.

What’s Blocked

The Babel preset inherits all AgentScript security rules:

Dangerous Babel options - plugins, sourceMaps, ast, babelrc, configFile
Disallowed presets - Any preset not in the security level’s allowlist
All AgentScript blocked constructs - eval, Function, process, etc.

Babel plugins are completely blocked because they can execute arbitrary code during transformation. Only presets from the allowlist can be used.

Creating the Preset

import { createBabelPreset } from '@enclave-vm/ast';

// Basic usage - inherits from AgentScript
const rules = createBabelPreset({
  securityLevel: 'STANDARD',
});

// With custom globals
const rulesWithGlobals = createBabelPreset({
  securityLevel: 'STANDARD',
  allowedGlobals: ['customHelper'],
});

// With all AgentScript options
const fullRules = createBabelPreset({
  securityLevel: 'SECURE',
  allowedGlobals: ['myGlobal'],
  requireCallTool: true,
  allowedLoops: {
    allowFor: true,
    allowForOf: true,
    allowWhile: false,
  },
});

Using with Enclave

The enclave automatically uses the Babel preset when configured:

import { Enclave } from '@enclave-vm/core';

const enclave = new Enclave({
  preset: 'babel',           // Uses createBabelPreset internally
  securityLevel: 'STANDARD', // Determines Babel limits
});

// Now Babel.transform is available inside the sandbox
await enclave.run(`
  const js = Babel.transform('<div/>', { presets: ['react'] });
  return js.code;
`);

API Reference

`createBabelPreset(options)`

Creates validation rules for the Babel preset.

function createBabelPreset(options?: BabelPresetOptions): ValidationRule[];

interface BabelPresetOptions extends AgentScriptOptions {
  // All AgentScriptOptions are supported
  // Security level determines Babel limits
}

`getBabelConfig(level)`

Gets Babel security configuration for a security level.

function getBabelConfig(level?: SecurityLevel): BabelSecurityConfig;

// Example
const config = getBabelConfig('SECURE');
// Returns: { maxInputSize, maxOutputSize, transformTimeout, allowedPresets }

`BABEL_SECURITY_CONFIGS`

Direct access to all security configurations.

const BABEL_SECURITY_CONFIGS: Record<SecurityLevel, BabelSecurityConfig>;

// Example
const strictConfig = BABEL_SECURITY_CONFIGS.STRICT;
const standardConfig = BABEL_SECURITY_CONFIGS.STANDARD;

AgentScript Preset - Base preset for code validation
Security Rules - Rule reference
Babel Transform (enclave-vm) - Using Babel in enclave
Security Levels - Security profiles

Get Started

Concepts

@enclave-vm/core

@enclave-vm/browser

@enclave-vm/ast

EnclaveJS Streaming

Guides

Examples

Troubleshooting

Overview

Basic Usage

Security Configurations

Configuration by Security Level

Configuration Options

Default Configurations

Allowed Globals

What’s Blocked

Creating the Preset

Using with Enclave

API Reference

`createBabelPreset(options)`

`getBabelConfig(level)`

`BABEL_SECURITY_CONFIGS`

​Overview

​Basic Usage

​Security Configurations

​Configuration by Security Level

​Configuration Options

​Default Configurations

​Allowed Globals

​What’s Blocked

​Creating the Preset

​Using with Enclave

​API Reference

​createBabelPreset(options)

​getBabelConfig(level)

​BABEL_SECURITY_CONFIGS

​Related

Overview

Basic Usage

Security Configurations

Configuration by Security Level

Configuration Options

Default Configurations

Allowed Globals

What’s Blocked

Creating the Preset

Using with Enclave

API Reference

`createBabelPreset(options)`

`getBabelConfig(level)`

`BABEL_SECURITY_CONFIGS`

Related