Environment and Global Access

/**
 * Get the global object in a cross-environment way
 * Handles globalThis, self, window, global, and fallback cases
 * @returns The global object for the current environment
 */
function getGlobalThis(): any;

/**
 * Check if a global variable name is allowed in Vue templates
 * Prevents access to potentially dangerous globals
 * @param key - Global variable name to check
 * @returns True if the global is safe to access
 */
function isGloballyAllowed(key: string): boolean;

/**
 * @deprecated Use isGloballyAllowed instead
 * Legacy name for isGloballyAllowed function
 */
function isGloballyWhitelisted(key: string): boolean;

/**
 * Create a map-based lookup function from comma-separated string
 * Used internally for creating fast lookup functions
 * @param str - Comma-separated string of keys
 * @returns Function that checks if key exists in the map
 */
function makeMap(str: string): (key: string) => boolean;

import { 
  getGlobalThis, 
  isGloballyAllowed, 
  isGloballyWhitelisted,
  makeMap 
} from "@vue/shared";

// Global object access across environments
const globalObj = getGlobalThis();

// In browser environment
if (typeof window !== 'undefined') {
  console.log(globalObj === window); // true
}

// In Node.js environment  
if (typeof global !== 'undefined') {
  console.log(globalObj === global); // true
}

// In Web Worker environment
if (typeof self !== 'undefined') {
  console.log(globalObj === self); // true
}

// Modern environments with globalThis
if (typeof globalThis !== 'undefined') {
  console.log(globalObj === globalThis); // true
}

// Global variable allowlist checking
console.log(isGloballyAllowed("Math")); // true - Math is allowed
console.log(isGloballyAllowed("console")); // true - console is allowed  
console.log(isGloballyAllowed("Date")); // true - Date is allowed
console.log(isGloballyAllowed("Array")); // true - Array is allowed
console.log(isGloballyAllowed("Object")); // true - Object is allowed

// Security - potentially dangerous globals are blocked
console.log(isGloballyAllowed("eval")); // false - eval is not allowed
console.log(isGloballyAllowed("Function")); // false - Function constructor blocked
console.log(isGloballyAllowed("window")); // false - direct window access blocked
console.log(isGloballyAllowed("document")); // false - document access blocked
console.log(isGloballyAllowed("localStorage")); // false - localStorage blocked

// Template usage simulation
function evaluateTemplateExpression(expr: string, globals: Record<string, any>) {
  // Check if global variables in expression are allowed
  const globalRefs = extractGlobalReferences(expr); // hypothetical function
  
  for (const ref of globalRefs) {
    if (!isGloballyAllowed(ref)) {
      throw new Error(`Global '${ref}' is not allowed in templates`);
    }
  }
  
  // Safe to evaluate expression
  return evaluateExpression(expr, globals);
}

// Legacy function (deprecated)
console.log(isGloballyWhitelisted("Math")); // true - same as isGloballyAllowed
// Note: This function is deprecated, use isGloballyAllowed instead

// Creating custom lookup maps
const allowedProps = makeMap("id,class,style,title,alt");
console.log(allowedProps("class")); // true
console.log(allowedProps("onclick")); // false

const htmlTags = makeMap("div,span,p,h1,h2,h3,button,input");
console.log(htmlTags("div")); // true
console.log(htmlTags("custom-element")); // false

// Safe global access pattern
const global = getGlobalThis();

// Feature detection
if ('fetch' in global) {
  // Fetch API available
}

if ('process' in global && global.process?.env) {
  // Node.js environment
}

// Environment-specific setup
function setupEnvironment() {
  const global = getGlobalThis();
  
  if (typeof window !== 'undefined') {
    // Browser environment
    setupBrowser(global);
  } else if (typeof global.process !== 'undefined') {
    // Node.js environment  
    setupNode(global);
  } else {
    // Other environment (Web Worker, etc.)
    setupGeneric(global);
  }
}