CODEWITHSUNDEEP
rxjsreactive-programming
Lionel Piroche
Lionel Piroche

Reputation: 252

How to combine two list of object in one list with Rxjs

I have 2 differents list of objects and i want to combine them together for exemple: 

listObj1 = [{name:'bob 1'}, {name:'bob 2'}]
listObj2 = [{pseudo:'Bob Razowski'}, {pseudo:'sponge bob'}]

result = [
   {name:'bob 1', pseudo:'Bob Razowski}
   {name:'bob 2', pseudo:'sponge bob'}
]

Can i do that with rxjs and how or if you have a better solution let me know

const characters = [];
const name$ = Observable.from(this.nameList)
                    .map(item => {
                        return {'name': item};
                    })

const pseudo$ = Observable.from(this.pseudoList)
                    .map(item => {
                        return {'pseudo': item};
                    })
Observable.zip(name$, pseudo$).subscribe(result => {
                        let char= {};
                        if(result.length > 1) {
                            char['name'] = result[0];
                            char['pseudo'] = result[1];
                            characters.push(char)
                        }
                    });

I started something like that but when i see the result, i can do it without rxjs. My question is more if it exists an other operator to do that.

thank

Upvotes: 1

Views: 1027

Answers (1)

ggradnig
ggradnig

Reputation: 14199

Well, you can do it with RxJS, but there is no obvious reason to do so, looking at your code snippet. One reason to do it reactively would be that you had really long lists and wanted to let the combination happen on (hypothetical) multiple threads. But in JavaScript that's not really practical, so for...of or Array.map are the right choices for this kind of task.

Anyhow, the RxJS solution would look like this:

zip(
    from(listOb1),
    from(listObj2)
).pipe(
    map(([one, two]) => Object.assign({}, one, two)),
    toArray()
)

Convert both lists into Observable streams with from, then zip them together and map each pair onto a new object using Object.assign. Collect the objects with toArray and done.

Upvotes: 2

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