What sets them apart?
The key distinction lies in the enhancement of source code readability, as demonstrated in your example. While there are only two functions showcased, envision dealing with a multitude of functions – it would result in cumbersome syntax like
function1().function2().function3().function4()
This convoluted structure becomes challenging to comprehend, especially when nested function calls come into play. Furthermore, certain editors such as Visual Studio Code impose restrictions on line length, typically capped at 140 characters. However, organizing the functions in a pipeline fashion can alleviate this issue.
Observable.pipe(
function1(),
function2(),
function3(),
function4()
)
By adopting this approach, clarity and legibility are significantly enhanced.
If no disparity exists, why implement the pipe function?
The purpose behind the PIPE() function is to amalgamate all functions that manipulate or return observables. Initially, an observable is passed into the pipe(), which then gets processed by each subsequent function within the pipeline.
The first function takes the observable, performs operations on it, modifies its value, and passes the transformed observable to the next function. This process continues iteratively until all functions contained within the pipe() have utilized the observable, resulting in a final processed observable. It's crucial to note that the original values within the initial observable remain unaltered. Subsequently, executing the observable with the subscribe() function allows for extracting the output value.
Why do these functions necessitate distinct imports?
Import requirements vary depending on where the function is situated within the rxjs package hierarchy. Generally, modules are housed in the node_modules folder in Angular projects.
import { class } from "module";
To illustrate, consider the following code snippet created in StackBlitz. It was manually generated without any automated tools or copied content. The intention here is to provide firsthand insight rather than regurgitating information from rxjs documentation. If you sought clarification on this platform, it implies a desire for simpler explanations.
- The classes pipe, observable, of, map are imported from their respective modules.
- Within the class body, the Pipe() function is utilized, as shown in the provided code.
The Of() function yields an observable that emits sequential numbers upon subscription.
The Observable remains unsubscribed at this point.
Calling Observable.pipe() prompts the pipe() function to use the designated Observable as input.
Subsequent executions involve each function processing the Observable data and passing it along the chain.
This sequence continues until all functions have operated on the Observable, delivering the processed result.
Ultimately, the pipe() function returns the manipulated Observable to a variable (e.g., obs in the sample code).
It's important to note that an observable will not emit any values until a subscriber has been registered. Hence, employing the subscribe() function is vital to trigger value emission. As soon as the observer subscribes, the of() function begins emitting values, subsequently undergoing transformations via pipe() before presenting the final outcome. For instance, after receiving '1' from of(), one is added via map() and returned accordingly. Extracting this output involves defining an argument within the subscribe() function callback.
To display the output, utilize the following format:
subscribe( function (argument) {
console.log(argument)
}
)
import { Component, OnInit } from '@angular/core';
import { pipe } from 'rxjs';
import { Observable, of } from 'rxjs';
import { map } from 'rxjs/operators';
@Component({
selector: 'my-app',
templateUrl: './app.component.html',
styleUrls: [ './app.component.css' ]
})
export class AppComponent implements OnInit {
obs = of(1,2,3).pipe(
map(x => x + 1),
);
constructor() { }
ngOnInit(){
this.obs.subscribe(value => console.log(value))
}
}
https://stackblitz.com/edit/angular-ivy-plifkg