What is * ngIf in angular?

The NgIf directive is used when you want to display or remove an element based on a condition. We define the condition by passing an expression to the directive which is evaluated in the context of it’s host component. The syntax is: *ngIf=“condition” See the documentation: https://angular.io/api/common/NgIf.

Can we use ngIf?

Using Angular’s NgIf

The syntax for NgIf is nice and simple, we simply can declare it on an element, or component, and let it work its magic. Placing the ngIf directive on a component, or element, will in fact hide or show that element based on the expression you pass it to be evaluated.

What is difference between * ngIf and Ng-if?

According to Angular documentation, ngIf is an Angular (v +2) directive , however, ng-if is an AngularJS (v 1. x) directive.

What is difference between ngIf and Ng show?

The Differences

ng-show (and its sibling ng-hide ) toggle the appearance of the element by adding the CSS display: none style. ng-if , on the other hand, actually removes the element from the DOM when the condition is false and only adds the element back once the condition turns true .

Where is ngIf used?

The NgIf directive is used when you want to display or remove an element based on a condition. If the condition is false the element the directive is attached to will be removed from the DOM .

Can we use ngIf and Ng-show together?

ng-if is better in this regard. Using it in place of ng-show will prevent the heavy content from being rendered in the first place if the expression is false. However, its strength is also its weakness, because if the user hides the chart and then shows it again, the content is rendered from scratch each time.

What is ngInit?

The ngInit directive allows you to evaluate an expression in the current scope. This directive can be abused to add unnecessary amounts of logic into your templates. There are only a few appropriate uses of ngInit : aliasing special properties of ngRepeat , as seen in the demo below.

Can I use NG-show and Ng-hide together?

2 Answers. Absolutely not. First of all, the two directives can trip over each other( see this JSFiddle, as provided by Joel Skrepnek), and is generally just bad design.

What is hidden in angular?

The DOM representation of the hidden attribute is a property also called hidden , which if set to true hides the element and false shows the element. Angular doesn’t manipulate HTML attributes, it manipulates DOM properties because the DOM is what actually gets displayed.

What is difference between ng show and Ng-hide?

The ng-show and ng-hide both are directive . The difference between is : ng-show directive will show the html element if expression resilts is true and ng-hide directive hide the html element if expression result is true .

Does ng show Remove from DOM?

ng-show/ng-hide does not remove the elements from DOM. It uses CSS styles to hide/show elements (note: you might need to add your own classes).

What does $event mean in angular?

$event is the event itself. The event binding (someevent) allows to bind to DOM events and to EventEmitter events. The syntax is exactly the same. For DOM events $event is the MouseEvent , KeyboardEvent , or the event value of the type of whatever event you listen to.

What is Property in angular?

In Angular 7, property binding is used to pass data from the component class (component. ts) and setting the value of the given element in the user-end (component. html). Property binding is an example of one-way databinding where the data is transferred from the component to the class.

What is the difference between @component and @directive in angular?

What is the difference between component and directive in Angular 6? A component is a directive used to shadow DOM to create and encapsulate visual behavior called components. They are typically used to create UI widgets. A Directive is usually used while adding behavior to an existing DOM element.

What is Handler in Angular?

In an event binding, Angular configures an event handler for the target event. … When the component or directive raises the event, the handler executes the template statement. The template statement performs an action in response to the event.

What is @input and @output in Angular 2?

The @Input is a decorator to mark an input property. The @Output is a decorator to mark an output property. The @Input is used to define an input property to achieve component property binding. The @Output is used to define output property to achieve custom event binding.

What is directives in Angular?

Directives are classes that add additional behavior to elements in your Angular applications. Use Angular’s built-in directives to manage forms, lists, styles, and what users see. … Attribute directives—directives that change the appearance or behavior of an element, component, or another directive.

What is scope on in AngularJS?

The Scope in Angular JS is the binding part between HTML (view) and JavaScript (controller) and it is a built-in object. It contains application data and objects. It is available for both the view and the controller. It is an object with available properties and methods.

What is event bubbling in Angular?

Event bubbling allows a single handler on a parent element to listen to events fired by any of its children. Angular supports bubbling of DOM events and does not support bubbling of custom events. Mixing the names of custom and DOM events (click, change, select, submit) could be problematic.

What is Ng blur in AngularJS?

Definition and Usage. The ng-blur directive tells AngularJS what to do when an HTML element loses focus. The ng-blur directive from AngularJS will not override the element’s original onblur event, both the ng-blur expression and the original onblur event will be executed.