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();
3
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.