basant307/AI_Governance_Project

1/**2 * @license3 * Copyright 2025 Google LLC4 * SPDX-License-Identifier: Apache-2.05 */6 7/**8 * Resolves environment variables in a string.9 * Replaces $VAR_NAME and ${VAR_NAME} with their corresponding environment variable values.10 * If the environment variable is not defined, the original placeholder is preserved.11 *12 * @param value - The string that may contain environment variable placeholders13 * @returns The string with environment variables resolved14 *15 * @example16 * resolveEnvVarsInString("Token: $API_KEY") // Returns "Token: secret-123"17 * resolveEnvVarsInString("URL: ${BASE_URL}/api") // Returns "URL: https://api.example.com/api"18 * resolveEnvVarsInString("Missing: $UNDEFINED_VAR") // Returns "Missing: $UNDEFINED_VAR"19 */20export function resolveEnvVarsInString(21  value: string,22  customEnv?: Record<string, string>,23): string {24  const envVarRegex = /\$(?:(\w+)|{([^}]+)})/g; // Find $VAR_NAME or ${VAR_NAME}25  return value.replace(envVarRegex, (match, varName1, varName2) => {26    const varName = varName1 || varName2;27    if (customEnv && typeof customEnv[varName] === 'string') {28      return customEnv[varName];29    }30    if (process && process.env && typeof process.env[varName] === 'string') {31      return process.env[varName]!;32    }33    return match;34  });35}36 37/**38 * Recursively resolves environment variables in an object of any type.39 * Handles strings, arrays, nested objects, and preserves other primitive types.40 * Protected against circular references using a WeakSet to track visited objects.41 *42 * @param obj - The object to process for environment variable resolution43 * @returns A new object with environment variables resolved44 *45 * @example46 * const config = {47 *   server: {48 *     host: "$HOST",49 *     port: "${PORT}",50 *     enabled: true,51 *     tags: ["$ENV", "api"]52 *   }53 * };54 * const resolved = resolveEnvVarsInObject(config);55 */56export function resolveEnvVarsInObject<T>(57  obj: T,58  customEnv?: Record<string, string>,59): T {60  return resolveEnvVarsInObjectInternal(obj, new WeakSet(), customEnv);61}62 63/**64 * Internal implementation of resolveEnvVarsInObject with circular reference protection.65 *66 * @param obj - The object to process67 * @param visited - WeakSet to track visited objects and prevent circular references68 * @returns A new object with environment variables resolved69 */70function resolveEnvVarsInObjectInternal<T>(71  obj: T,72  visited: WeakSet<object>,73  customEnv?: Record<string, string>,74): T {75  if (76    obj === null ||77    obj === undefined ||78    typeof obj === 'boolean' ||79    typeof obj === 'number'80  ) {81    return obj;82  }83 84  if (typeof obj === 'string') {85    return resolveEnvVarsInString(obj, customEnv) as unknown as T;86  }87 88  if (Array.isArray(obj)) {89    // Check for circular reference90    if (visited.has(obj)) {91      // Return a shallow copy to break the cycle92      return [...obj] as unknown as T;93    }94 95    visited.add(obj);96    const result = obj.map((item) =>97      resolveEnvVarsInObjectInternal(item, visited, customEnv),98    ) as unknown as T;99    visited.delete(obj);100    return result;101  }102 103  if (typeof obj === 'object') {104    // Check for circular reference105    if (visited.has(obj as object)) {106      // Return a shallow copy to break the cycle107      return { ...obj } as T;108    }109 110    visited.add(obj as object);111    const newObj = { ...obj } as T;112    for (const key in newObj) {113      if (Object.prototype.hasOwnProperty.call(newObj, key)) {114        newObj[key] = resolveEnvVarsInObjectInternal(115          newObj[key],116          visited,117          customEnv,118        );119      }120    }121    visited.delete(obj as object);122    return newObj;123  }124 125  return obj;126}127