Shouldnt
from([])only result in completion? Seems like it just freezes
yes should be same as EMPTY
I posted the question on stackoverflow: https://stackoverflow.com/questions/64496237/rxjs-parallel-http-call-to-paginated-api-using-nestjs-httpservice
It have bountied for 50 reputation point, i got stuck on this batching task
docs say that "The output Observable only completes once all input Observables have completed" - so why does it complete?
merge(sub)
Notice
merge([sub])
.subscribe(
(e) => console.log('subscribe' + e),
() => {},
() => console.log('complete'));will emit
subscribe[object Object]
complete
the [object Object] here is the behaviorsubject.
merge(sub1, sub2)
zip, concat, merge, etc , is treated like an array of arguments.
getLastCommits(): Observable<PRData[]> {
return this.bitbucketService
.getLatestCommits()
.pipe(
concatMap((listOfCommits: any) => listOfCommits.values),
map((commit: any) => {
const hash = commit.hash;
return this.bitbucketService.getPullRequestIDfor(hash)
.pipe(
map(id => ({
commitHash: hash,
pullRequestID: id
} as PRData))
);
})
);
}I'm trying to do this convoluted thing....
Bitbucket service gets my last 10 commits in an object with an array called values containing all my commits
I'm trying to use concatMap to peel away that object into an individual object for every value/commit in that object
From here I want to take the has for every commit....
reach out and get the pull request data for that hash
and somehow wrap and return both the hash and the pull request ID returned from that new subscription call
In the end I want an array of { commitHash, pullRequestID }, { commitHash, pullRequestID }, { commitHash, pullRequestID }
But right now with this I seem to be getting on single { commitHash, pullRequestID }
Ignoring the fact that at this point I don't really know what I'm doing, what am I doing wrong?
getLastCommits(): Observable<PRData[]> {
return this.bitbucketService
.getLatestCommits()
.pipe(
map((listOfCommits: any) => listOfCommits.values),
tap((whatever: any) => console.log(whatever)),
map((listOfCommits: any) => {
return listOfCommits.map((commit: any) => {
const hash = commit.hash;
return this.bitbucketService.getPullRequestIDfor(hash)
.pipe(
map(id => ({
commitHash: hash,
pullRequestID: id
} as PRData))
);
});
}),
tap((whatever: any) => console.log(whatever)),
);
}where I have an array of observables.... (possibly bad because it's nested)
Is there a way to unwrap all those inner subscriptions and accumulate all this data? when I subscribe?
Was my other way better?
source.mergeMap(e => httpCall(e))
map((listOfCommits: any) => listOfCommits.values),At this point I have an array,
using
mergeMap((listOfCommits: any) => {
return listOfCommits.map((commit: any) => {here instead of map just tells me that mergeMap is deprecated and that I should use an inner map instead... I'm not sure what that means or if this is where I was supposed to mergeMap to begin with
map<T, T2>(e => httpcall(e)) you're going from Observable<T> -> Observable<Observable<T2>> right?mergeMap will flatten this (as will concatMap, exhaustMap, switchMap, but in different concurrent patterns). Thus your Observable<Observable<T2>> back to <Observable<T2>.
Just like flatten on an array T[][] will give T[].
mergeMap?
mergeMap(selector, resultSelctor) in favor of mergeMap(selector) https://rxjs-dev.firebaseapp.com/guide/v6/migration#howto-result-selector-migration
mergeMap on an array will flatten the array. That on itself could be useful, but not the primary purpose of mergeMap. the selector should return an observable that is then merged together with other observables emitted from other runs of the selector.