Awesome
RxJS-toolbox - set of custom operators and handy factory functions for RxJS
*Note: updated to Angular 16.x in version 2.2.0
Installation
Install using NPM CLI
npm install --save rxjs-toolbox
forkJoin-transparent
A combination operator that combines multiple sources and returns their last emitted data as well as percentage of their completion.
Usage
forkJoinWithProgress
import { ajax } from 'rxjs/ajax';
import { merge } from 'rxjs';
`import { forkJoinWithProgress } from 'rxjs-toolbox';`
import {tap, mergeMap, ignoreElements} from 'rxjs/operators';
const getUserDetails = userIdsList => {
const arrayOfObservables = userIdsList.map(userId =>
ajax('https://jsonplaceholder.typicode.com/comments/' + userId)
)
return forkJoinWithProgress(arrayOfObservables)
}
const result$ = getUserDetails([1, 2, 15]);
result$.pipe(
mergeMap(([finalResult, progress]) => merge(
progress.pipe(
tap((value) => console.log(`${value} completed`)),
ignoreElements()
),
finalResult
))
).subscribe(values => console.log(values), console.warn);
// Output:
// 33.333333333333336 completed
// 66.66666666666667 completed
// 100 completed
// final value: (3) [{…}, {…}, {…}]
waitUntil
I found an interesting #rxjs custom operator in auth0-angular interceptor codebase: waitUntil
It holds until the param observable emits first value- and then switches to the source
######Params: isLoaded$
isLoaded$ // - some observable we wait for
...
of(route).pipe(
waitUntil(isLoaded$)
)
...
Helper functions
timeRange
Function to create Observable that will emit values with specified delays ######Params: range - array of objects with special structure [{value: <some value>, delay: <delayInMs>},...]
isRelative - if true = next emissions is scheduled only after previous is complete (so delays are summarized).
if false - all values are scheduled at once (delay values are absolute in relation to the moment of subscription)
const range$ = timeRange([
{value: 15, delay: 1500}, // 1500ms
{value: 15, delay: 2500} // 2500ms
])
const range2$ = timeRange([
{value: 15, delay: 1500}, // 1500ms
{value: 15, delay: 2500} // 1500+2500
], true);
finalizeWithValue
Provides (unlike original finalize from RxJS) source$'s last emitted value (if any) in format {value: <lastValue>}.
If source$ completes with noe emitted value - provides undefined.
Author - Ben Lesh, taken here
from([1,3]).pipe(
finalizeWithValue((lastEmittedValue) => console.log(lastEmittedValue)) // 3
)
Want to learn RxJS?
Try my "Hands-on RxJS for Web Development" video-course!