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# Test Environment
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Custom JSDOM environment optimized for Angular testing with proper global setup and Angular-specific configurations.
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## Capabilities
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### JestJSDOMEnvironment Class
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Custom Jest environment that extends the abstract JSDOM environment with Angular-specific optimizations and JSDOM integration.
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```typescript { .api }
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/**
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 * Custom JSDOM environment for Angular testing
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 * Extends Jest's abstract JSDOM environment with Angular optimizations
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 */
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class JestJSDOMEnvironment extends BaseEnv {
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  /**
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   * Creates a new JestJSDOMEnvironment instance
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   * @param config - Jest environment configuration
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   * @param context - Environment context from Jest
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   */
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  constructor(config: JestEnvironmentConfig, context: EnvironmentContext);
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}
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interface JestEnvironmentConfig {
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  projectConfig: Config.ProjectConfig;
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  globalConfig: Config.GlobalConfig;
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}
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interface EnvironmentContext {
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  console: Console;
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  docblockPragmas: Record<string, string | string[]>;
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  testPath: string;
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}
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interface BaseEnv {
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  constructor(config: JestEnvironmentConfig, context: EnvironmentContext, jsdom: any);
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  global: any;
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  moduleMocker: any;
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  fakeTimers: any;
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  setup(): Promise<void>;
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  teardown(): Promise<void>;
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  runScript(script: any): any;
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}
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```
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**Usage Examples:**
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```javascript
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// jest.config.js - Using the custom environment
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module.exports = {
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  testEnvironment: 'jest-preset-angular/environments/jest-jsdom-env',
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  // other configuration...
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};
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// Or in preset configuration
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const { createCjsPreset } = require('jest-preset-angular/presets');
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module.exports = createCjsPreset({
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  testEnvironment: 'jest-preset-angular/environments/jest-jsdom-env'
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});
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```
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### Environment Features
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**JSDOM Integration:**
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- Uses the latest JSDOM version for DOM simulation
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- Provides browser-like environment for Angular components
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- Supports DOM manipulation and events
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**Angular Optimizations:**
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- Pre-configured for Angular testing requirements
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- Handles Angular's zone.js integration
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- Supports Angular's change detection in tests
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**Debugging Support:**
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- Logs JSDOM version information for debugging
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- Integrates with ts-jest logging system
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- Provides detailed error reporting
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### Environment Types
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The package provides environment type definitions for configuration:
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```typescript { .api }
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type JSDOMEnvironment = 'jsdom' | 'jest-preset-angular/environments/jest-jsdom-env';
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```
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**Available Environments:**
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- `'jsdom'`: Standard Jest JSDOM environment
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- `'jest-preset-angular/environments/jest-jsdom-env'`: Custom Angular-optimized environment
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### Configuration in Presets
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The environment is automatically configured when using preset functions:
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```javascript
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// Default environment (jsdom)
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const config = createCjsPreset();
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// Custom Angular environment
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const config = createCjsPreset({
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  testEnvironment: 'jest-preset-angular/environments/jest-jsdom-env'
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});
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```
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### Environment Context
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The environment provides proper context for Angular testing:
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**Global Objects:**
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- `window` object with DOM APIs
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- `document` object for DOM manipulation
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- `navigator` object for browser simulation
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**Angular Integration:**
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- Proper `this` context for component testing
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- Support for Angular's dependency injection
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- Integration with Angular testing utilities
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### Browser Simulation
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The environment simulates browser features needed for Angular:
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**DOM APIs:**
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- Element creation and manipulation
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- Event handling and propagation
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- CSS selector queries
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**Browser Features:**
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- LocalStorage and SessionStorage
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- History API for routing tests
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- Fetch API for HTTP testing
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**Performance:**
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- Optimized for test execution speed
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- Minimal overhead for simple tests
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- Efficient memory usage
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### Compatibility
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The environment is compatible with:
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**Angular Versions:**
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- Angular 18+
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- Angular 19+
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- Angular 20+
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**Node.js Versions:**
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- Node.js 18.19.1+
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- Node.js 20.11.1+
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- Node.js 22.0.0+
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**Jest Versions:**
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- Jest 30.0.0+
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### Environment Setup
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The environment automatically handles setup required for Angular testing without additional configuration:
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```typescript
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// No manual setup required - environment handles:
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// - JSDOM initialization
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// - Angular testing utilities setup
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// - Zone.js configuration
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// - Error handling setup
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```