Angular Component Performance Monitor

Performance is crucial for a smooth and responsive user experience in Angular applications. This challenge tasks you with creating a reusable Angular service that monitors the rendering time of Angular components, providing insights into potential bottlenecks and areas for optimization. The service should log component rendering times to the console, allowing developers to identify slow-loading components.

Problem Description

You need to build an PerformanceMonitorService in Angular that tracks and logs the time it takes for Angular components to render. The service should:

1. Intercept Component Rendering: Utilize Angular's lifecycle hooks to intercept the rendering process of components. Specifically, focus on the AfterViewChecked hook, which is called after Angular has fully checked a component's view and child views.
2. Time Measurement: Within the AfterViewChecked hook, measure the time taken for the component to render. This should be a relatively precise measurement.
3. Logging: Log the component's name and the rendering time to the console. The log message should be clear and informative.
4. Selective Monitoring: Provide a mechanism to enable/disable monitoring for specific components. This can be achieved through a component-specific configuration or a global enable/disable flag.
5. Reusability: The service should be designed to be easily integrated into different Angular projects and components without requiring significant modifications.

Expected Behavior:

• When a component's view is checked, the PerformanceMonitorService should record the time elapsed since the last view check.
• The service should log the component's name and rendering time to the console.
• Monitoring should be configurable, allowing developers to enable or disable it for specific components or globally.
• The service should not introduce significant overhead to the application's performance.

Edge Cases to Consider:

• Components with complex templates or data bindings might take longer to render.
• Components that frequently re-render due to change detection can generate a large number of log messages. Consider adding a threshold for logging (e.g., only log times exceeding a certain duration).
• Components that are dynamically created or destroyed should be handled gracefully.
• The service should not interfere with the normal functioning of the Angular application.

Examples

Example 1:

Input: A component named 'MyComponent' with a moderately complex template.
Output:  Console log: "MyComponent rendering time: 12.5ms" (or a similar value)
Explanation: AfterViewChecked is triggered, the time taken for rendering 'MyComponent' is measured and logged.

Example 2:

Input: A component named 'SlowComponent' with a very complex template and many data bindings.  Monitoring is enabled globally.
Output: Console log: "SlowComponent rendering time: 85.2ms" (or a similar, higher value)
Explanation: The service detects the longer rendering time of 'SlowComponent' and logs it.

Example 3:

Input: A component named 'FastComponent' with a simple template. Monitoring is enabled, but a threshold of 20ms is set. The rendering time is 10ms.
Output: No console log.
Explanation: The rendering time is below the threshold, so no log message is generated.

Constraints

• Performance: The service should not introduce more than a 5% overhead to the application's rendering performance. Excessive logging or complex calculations should be avoided.
• Angular Version: The solution should be compatible with Angular 14 or later.
• TypeScript: The code must be written in TypeScript.
• Logging: Use console.log for logging. Consider using a more sophisticated logging mechanism in a production environment.
• Component Identification: The service should reliably identify the component being rendered. Using the component's constructor or a dedicated property is recommended.

Notes

• Consider using RxJS Observables to manage the lifecycle events and avoid blocking the main thread.
• Think about how to handle components that are dynamically created and destroyed. You might need to subscribe and unsubscribe to lifecycle events.
• The AfterViewChecked hook is called frequently. Be mindful of the performance impact of your code within this hook. Avoid computationally expensive operations.
• A simple configuration mechanism (e.g., a boolean flag or an array of component names) can be used to control which components are monitored.
• Focus on creating a clean, reusable, and performant service. Don't overcomplicate the solution.