Angular & RxJS Tips #5: Multiple Http calls - combineLatest vs forkJoin

In RxJS you can make multiple REST calls, wait that all of them are completed and get a single result.
You can use forkJoin and combineLatest RxJS operators to achieve this result.
So, what’s the difference?
Level: intermediate
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[@g3co875]

these short videos are programming gems, please, keep doing them! thanks for your time!

[@meraku9390]

this is a very precise and concise video, without using those default examples, excellent !!

[@LeonardoBuscemi]

I love this video! Thank you so much

[@ahmadbenchakhtir5787]

broooooooooooooo, This Explain are amaziiiiiiing.

[@FabioBiondi]

thank you for the feedback Ahmad

[@MelodiousMusic2458]

Hey, it is little bit difficult to understand the accent but quality of content is very good. By the way what is your native language?

[@FabioBiondi]

thank you. I'm trying to improve my english but it will be a looong journey 🤣

[@MikeDePetris]

complex things

[@MikeDePetris]

Can you help me on a different situation please, that is not really nested calls but instead a sequence of call where the results have to be concatenated. I call service.getItems(p1).suscribe(res=>{this.allItems = res; service.getItems(p2).subscribe(res =>{this.allItems = this.allItems.concat(res); ... many nested calls, you get?

[@FabioBiondi]

If you need to concat previous result with the new one you should do something similar (hard to write here in a YT comment).
If you prepare a stackblitz with a real world case I can help you more.
service.getItems(p1)
.pipe(
mergeMap(res => service.getItems2(res).pipe(map(res2 => [...res2, ...res2]) )
.. so the next operator will receive the merge of previous results and you can do another mergeMap doing the same...
)
.subscribe(res => {
// res is now the merge of previous results
})

[@MikeDePetris]

​@@FabioBiondi so many thanks for the quick answer, will have a try and prepare a stackblitz for sure, as I am procratinating this issue for too long

[@MikeDePetris]

@@FabioBiondi I made you editor of a stackblitz Data API Rest Angular (forked)

[@FabioBiondi]

@@MikeDePetris where can I find it?

[@letri8757]

@@FabioBiondi When i use mergeMap, i always make sure the inner observable is a completed observable. If not, will have a memory leak ! Is it a right things ?