Angular Components Interaction Methods – A Quick Study

Ravi Chandhar P B

April 17, 2020

Last updated: April 2, 2024

Introduction – A Brief Into Angular Components Interaction Methods

Angular is a popular front-end framework that allows developers to create complex, dynamic web applications. One of the key features of Angular is its ability to facilitate communication between components, often known as an angular interaction between components.

With the evolution of Angular versions, the interaction methods among Angular components have experienced remarkable changes, enabling seamless communication and collaboration between different parts of the application. Thus, in this quick study, we will explore the different Angular components interaction methods.

What Are Components In Angular?

In Angular, components are the fundamental building blocks of the user interface. They encapsulate the template, logic, and styles for a specific part of the application, allowing for modular and reusable development. Components handle rendering and user interactions within the application’s views.

In all the calculations done manually or programmatically, the data collected gets shared and evaluated in a particular process to attain certain end results. Across sectors, sharing of data plays a vital role in computing end solutions.

With Angular’s robust component interaction method, developers can seamlessly communicate between different parts of the application, enhancing modularity and maintainability while reaping the benefits of angular web application development.

Now, let’s get into a comprehensive view of how the data get shared among multiple components in an Angular application. Even before getting started with the Angular Project, is important to a clear understanding of the key concept of Data Sharing.

Nonetheless, if you have multiple components in your angular application and necessitates inter- component communication, then Angular provides you some features and angular components interaction methods.

Hence, in this section, let’s get a study on the different angular components interaction methods used for sharing data between the angular components.

Understanding Component Communication

Component communication in Angular refers to the mechanism through which different components within an Angular application exchange data and coordinate actions. This interaction between components is essential for building dynamic and interconnected web applications.

Angular provides several ways to facilitate component communication:

Input and Output Properties: Components can communicate by passing data between parent and child components using input and output properties. The parent component can bind data to the child component’s inputs, and the child component can emit events through its outputs to notify the parent about certain actions or changes.

Services: Angular services act as intermediaries for sharing data and functionality across different components. Components can inject and use the same service instance, enabling them to communicate indirectly by sharing information stored in the service.

RxJS Observables: Observables are a powerful feature of the Reactive Extensions for JavaScript (RxJS) library, which is included with Angular. Components can use observables to subscribe to changes and events, allowing them to react to data updates and trigger actions accordingly.

EventEmitter: The EventEmitter class from the @angular/core module can be used to create custom events for communication between components. This is especially useful when a child component needs to notify its parent about a specific event.

ViewChild and ContentChild: These decorators enable a component to access and interact with its child components or elements, allowing for more direct communication and manipulation.

NgRx: For complex state management and communication, NgRx provides a state management solution using Redux principles. It offers a centralized store that components can interact with, maintaining a predictable and efficient communication flow.

Choosing the appropriate method of communication depends on the specific requirements of your Angular application. By mastering component communication techniques, developers can create well-organized, modular, and responsive applications that deliver a seamless user experience.

Angular Components Interaction Methods

Data sharing between the angular components is possible with the following ways,

• Sharing Data from Parent to Child:  @Input
• Sharing Data from Child to Parent:  @ViewChild
• Sharing Data from Child to Parent:  @Output & EventEmitter 
• Sharing Data Between Various Components:  Service

Sharing Data from Parent to Child:  @Input

Firstly, parent to child component communication in angular provides a decorator called @Input decorator which can be used to pass data from Parent to Child.

This is one of the most common methods of sharing data from Parent to Child in Angular application. Now, let’s see the working of the @Input decorator in the following snippets,

# calibraint-parent.component.ts

# calibraint-child.component.ts

Sharing Data from Child to Parent:  @ViewChild

Angular provides this  @ViewChild() decorator which can be used to inject one component to another. Now, this is made possible by giving the parent access to its attributes and functions.

Also, to be noted that the Child component gets available only after the view gets initialized. So, we need to implement the AfterViewInit lifecycle hook to get the data from the child.  Now, let’s see the working of the @ViewChild decorator in the following snippets,

# calibraint-parent.component.ts

# calibraint-child.component.ts

Sharing Data from Child to Parent:  @Output & EventEmitter

The @Output decorator allows marking a class field as an output property and supplies configuration metadata.

In this method, the child component will emit the data, which will be received by the parent component. Firstly, if we need to send data from the child to the parent, then it is required to emit the data from the child.

To make it function so, we need to create a function in the parent to receive the message and set it equal to the variable of the message. The @Output decorator now allows declaring a message event variable in the child.

So, now the parent can subscribe to this message event that the child component emits and then executes the receive message function whenever this event occurs.

This ideal condition and this approach are helpful when you want to share some data on some events like button clicks, users and other form-related events.

# calibraint-parent.component.ts

# calibraint-child.component.ts

Sharing Data Between Various Components – Angular Component To Component Communication:

Component to component communication in angular has Service which is class that holds the data or functions based on the application’s need and also stores the logic in the file, this allows us to reuse the code with the different components when it requires.

In the service, we create a private BehaviorSubject that holds the current value of the message. Then, we have to define a current message variable to handle this data stream as an observable that will be used by the components.

Lastly, we have to create a function that calls next on the BehaviorSubject to change its value.

# calibraint-data.service.ts

Components of the parent, child, and sibling will receive the same values. We inject the CalibraintDataService into the constructor, then subscribe to the observable current message and set its value equal to the variable message.

Now if we create a function in any of these components which changes the message value. When the new data is executed this function will automatically transmit it to all other components.

# calibraint-parent.component.ts

# calibraint-sibling.component.ts

Conclusion

In conclusion, Angular offers various ways for angular components interaction methods such as Input/Output binding, ViewChild/ViewChildren, and Services. Input/Output binding is a simple and effective way for a parent component to pass data and events to its child components, while ViewChild/ViewChildren provides a way for components to access child components directly. Services, on the other hand, offer a centralized and reusable way for components to share data and logic across an angular web application development.

Nonetheless, in Angular, components interaction methods, such as @Input and @Output, facilitate seamless communication between different components, enabling efficient handling and validation of data in Angular Forms.

By understanding these methods, developers can create more efficient and scalable applications with Angular. Ultimately, the choice of which method to use depends on the specific needs of the application and the developers’ preference.

In this post, it is depicted on how to share data between parent and child components using @Input(), @Output and EventEmitter and also on the methods to share data between different components.

Data sharing is a very important concept, and everybody requires sharing data between the application components. Hope you had an insightful overview of the data sharing concept in angular components interaction methods. 

Reference:- https://angular.io/docs

Credits:- https://carbon.now.sh/

Frequently Asked Questions On Angular Components

What Are Angular Components?

Angular components are reusable building blocks in Angular applications that encapsulate the logic and UI for a specific part of the user interface. They consist of a TypeScript class, an HTML template, and optional styles, enabling the creation of modular and maintainable web applications.

Ravi Chandhar P B

April 17, 2020

Last updated: April 2, 2024

5