What is detectChanges?

This one is used to run change detection for the tree of components starting with the component that you trigger detectChanges() on. So the change detection will run for the current component and all its children.

What is the use of ChangeDetectorRef?

ChangeDetectorRef allows you to manipulate this tree, angular runs the change detection every time there is a change. For example, when you have a large amount of data and there is a change in that data, angular will render the view again, if the data changes every second, your application will become slower.

What is ChangeDetectionStrategy?

ChangeDetectionStrategylink The strategy that the default change detector uses to detect changes.

What does detectChanges do Angular?

The detectChanges method runs the change detector for the current component and its children. For once, it can even run change detection on a component that has detached change detector without reattaching it.

What is runOutsideAngular?

Returns. T. Running functions via runOutsideAngular allows you to escape Angular’s zone and do work that doesn’t trigger Angular change-detection or is subject to Angular’s error handling. Any future tasks or microtasks scheduled from within this function will continue executing from outside of the Angular zone.

How do I stop ExpressionChangedAfterItHasBeenCheckedError?

A good way to fix the ExpressionChangedAfterItHasBeenCheckedError is to make Angular aware of the fact that you have changed the code after it has completed its first check. You can do this by using setTimeout to make the error go away.

What is ApplicationRef in Angular?

ApplicationRef contains reference to the root view and can be used to manually run change detection using tick function. Invoke this method to explicitly process change detection and its side-effects.

What is OnPush strategy?

The main idea behind the OnPush strategy manifests from the realization that if we treat reference types as immutable objects, we can detect if a value has changed much faster. When a reference type is immutable, this means every time it is updated, the reference on the stack memory will have to change.

What is .subscribe in Angular?

Subscribe() is a method in Angular that connects the observer to observable events. Whenever any change is made in these observable, a code is executed and observes the results or changes using the subscribe method. Subscribe() is a method from the rxjs library, used internally by Angular.

Where should we call the detectChanges method?

It will run change detection on marked component even though they are using the OnPush strategy. detectChanges — When you call this method on changeDetectorRef provider, it will run change detection from the current component and all it’s descendants.

What is Zonejs?

Zone. js is a library created by Brian Ford in 2010 and is inspired by Dart. It provides a concept called Zone , which is an execution context that persists across async tasks. A Zone can: Provide execution context that persist across async tasks.

What causes ExpressionChangedAfterItHasBeenCheckedError?

What is ExpressionChangedAfterItHasBeenCheckedError? The ExpressionChangedAfterItHasBeenCheckedError error is thrown up when the binding expression changes after being checked by Angular during the change detection cycle.

What is ngAfterViewInit?

ngAfterViewInit()link A callback method that is invoked immediately after Angular has completed initialization of a component’s view. It is invoked only once when the view is instantiated.

What is ViewRef in angular?

ViewRef It is the smallest grouping of elements which are created and destroyed together. Angular philosophy encourages developers to see the UI as a composition of Views, not as a tree of standalone HTML tags. Angular supports two types of views: Embedded Views which are linked to a Template.

What is Componentref in angular?

ComponentReflink Represents a component created by a ComponentFactory . Provides access to the component instance and related objects, and provides the means of destroying the instance.

What is the difference between OnPush and default change detection?

OnPush means that the change detector’s mode will be set to CheckOnce during hydration. Default means that the change detector’s mode will be set to CheckAlways during hydration.

What is changeDetection OnPush?

The OnPush strategy changes Angular’s change detection behavior in a similar way as detaching a component does. The change detection doesn’t run automatically for every component anymore. Angular instead listens for specific changes and only runs the change detection on a subtree for that component.

What is interceptor in Angular?

Interceptor is a special Angular Service that can be used to intercept all the request and response calls and modify them to our requirement.