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What is input and output Angular?
They are a mechanism to send/receive data from one component to another. Input is used to receive data in whereas Output is used to send data out. Output sends data out by exposing event producers, usually EventEmitter objects.
What are the inputs and outputs of Angular compilation?
Angular 2 Components: Inputs and Outputs
- The “inputs” property passed to the @Components decorator lists “myname” as a component property that can receive data.
- The “outputs” property lists “myevent” as a custom event that ParentComp can emit which its parent will be able to receive.
What is input and output decorator in Angular?
@Inoput decorator is used to pass data (property binding) from parent to child component. The component property should be annotated with @Input decorator to act as input property. Let’s explore it practically. I have created an angular application which is AngApp.
What is the lifecycle of Angular?
A component instance has a lifecycle that starts when Angular instantiates the component class and renders the component view along with its child views. The lifecycle ends when Angular destroys the component instance and removes its rendered template from the DOM.
What is the use of Angular lifecycle hooks such as ngOnInit?
ngOnInit: Called once upon initialization of the component. ngDoCheck: Use this hook instead of ngOnChanges for changes that Angular doesn’t detect. It gets called at every change detection cycle, so keeping what it does to a minimum is important for performance.
What are input properties in Angular?
Inputlink. Decorator that marks a class field as an input property and supplies configuration metadata. The input property is bound to a DOM property in the template. During change detection, Angular automatically updates the data property with the DOM property’s value.
What does the @ input and @ output do in angular?
@Input defines the input property in the component, which the parent component can set. The @output defines the output property (event), which we raise in the child component using the EventEmitter. The parent listens to these events.
What does the @ input decorator do in angular?
@ Input () allows a parent component to update data in the child component. Conversely, @ Output () allows the child to send data to a parent component. The @ Input () decorator in a child component or directive signifies that the property can receive its value from its parent component.
How does a component receive data in Angular 2?
Angular 2 components can receive data from their parent as long as the receiving component has specifically said it’s willing to receive data. Similarly, components can send data to their parents by trigger an event the parent listens for. Let’s look at how the component hierarchy behaves.
Which is an @ ouput property in Angular 2?
The input’s onclick attribute/event is considered in Angular 2 an @Ouput property, because it sends info as an $event object to external components that might use it. See: https://angular.io/docs/ts/latest/guide/template-syntax.html#!#inputs-outputs.