Câu trả lời What is a Service, and when will you use it?
In Angular, a Service is a broad category that encompasses any value, function, or feature that an application needs. Typically, a Service is a class with a narrow, well-defined purpose. It should do something specific and do it well, encapsulating functionality that isn't directly tied to a view and can be shared across components[15].
Understanding Angular Services
Services in Angular are designed to be reusable across different components of an application. They are used to organize and share code such as data connections, business logic, or algorithms independent of any UI components. This separation of concerns ensures that the components are lean and focused only on handling the user interface, while services handle data and logic[3][8][9].
Angular Services are singleton objects that get instantiated only once during the lifetime of an application. They are provided at the root level or in a specific component, making them available throughout the application or within a specific context[3][4][5][15].
When to Use Services in Angular
Data Handling: Services are ideal for managing data operations, such as fetching data from a server, validating user input, or performing CRUD operations on a database. This keeps the data handling logic separate from the UI logic[3][8][9].
Business Logic: Services can encapsulate business logic that needs to be executed independently of any particular view or component. This could include calculations, state management, or rules processing[3][15].
Utility Functions: If there are functions that are useful across various parts of your application, such as logging or error handling, these can be included in a service to avoid code duplication and facilitate easier maintenance[3][9].
API Integration: For applications that interact with external APIs, services can manage all HTTP requests. This centralizes the configuration for these APIs and makes it easier to handle changes and errors[1][2][5].
Component Communication: Services can be used to enable communication between components that don't have a direct relationship (such as parent-child or siblings). By using services, data or events can be shared across components[6][10]...
