Angular’s new output() API in Angular v17.3 with practical example | output() API in Angular v17.3

 In Angular, components often need to communicate with their parent components by emitting events or data. The traditional way to achieve this has been using the @Output decorator with EventEmitter. While it works, the new output() API (introduced in Angular version 17.3 as a developer preview) offers several advantages:

  • Simpler and Safer: It provides a more concise and less error-prone way to declare outputs.
  • Type Safety: It enforces stricter type checking, preventing potential runtime errors due to incorrect data types being emitted.
  • Consistency: It aligns with other function-based APIs like input() and model() in Angular, making your code more consistent and easier to understand

Limitation to using a traditional approach to declaring outputs or @output

The traditional approach to declaring outputs in Angular components using @Output and EventEmitter had some limitations that the new output() and outputFromObservable() APIs aim to address:

1. More Boilerplate Code:

  • The old approach required manual instantiation of an EventEmitter for each output:

@Output() someEvent =newEventEmitter();

  • This could lead to more verbose code, especially for components with multiple outputs.

2. Potential Type Safety Issues:

  • With EventEmitter, you had to manually ensure that the emitted data matched the desired type.
  • This could lead to runtime errors if you accidentally emit the wrong data type.

3. Less Consistent Style:

  • The use of EventEmitter didn't align with other function-based Angular APIs like @Input() and [(ngModel)].
  • This could make code less readable and maintainable.

How output() and outputFromObservable() address these limitations:

  • Concise Syntax: Both new APIs offer a more concise way to declare outputs, removing the need for manual EventEmitter creation.

         // New approach
2  someEvent = output();
4// Old approach
5@Output() someEvent =new EventEmitter();

  • Improved Type Safety: These APIs enforce stricter type checking, ensuring emitted values match the declared type. This helps prevent runtime errors.

  • Consistent Style: They align with other function-based APIs, making the code more consistent and easier to understand.

In summary, the new output() and outputFromObservable() APIs offer a more streamlined, type-safe, and consistent approach to declaring outputs in Angular components compared to the traditional @Output and EventEmitter.

Angular’s new output() API in 

Angular v17.3 with a practical example 


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