What is the method for checking dirty data in Angular?

In Angular, dirty checking is implemented through the Zone.js library. Zone.js is a library used to intercept and track asynchronous operations, capturing the start and end of asynchronous operations and running dirty checking after each operation.

When data in an Angular application changes, Angular marks the changes as dirty data. Then, Zone.js initiates a dirty check loop, which goes through all components and bindings in the application and updates the view.

There are two types of methods for checking dirty data.

1. Manually trigger dirty data check: In some cases, Angular may not be able to automatically detect data changes, so you can manually trigger a dirty data check using the detectChanges method of ChangeDetectorRef. For example, after an asynchronous operation is completed, you can call detectChanges method to update the view.
2. Automatic triggering of dirty data checking: Angular will automatically track most data changes, including user interactions, HTTP request responses, timers, etc. After these asynchronous operations are completed, Angular will automatically trigger dirty data checking and update the view.

In a nutshell, Angular utilizes Zone.js for dirty checking, which can be triggered manually or automatically.