Angular - modify observable value

Question

I have a function in my angular component that receives an observable. I need to modify the object inside the observable and then 'put it back inside' the observable again and return it. This is my code so far:

myImmobili =  Observable<Valutazione[]>;
newImmobile(immobili: Observable<Valutazione[]>) {

    immobili.subscribe(
      imm => { 
        console.log(imm);
        imm.push(new Valutazione());
        console.log(imm);
        this.myImmobili = //some code here
      }
    );
  }

Can anyone give me a hint? Maybe there's even a better way to modify my array without subscribing to it, but I couldn't find it. Thanks.

EDIT

newImmobile() {

    this.immobili.subscribe(i => console.log('before', i));
    this.immobili.map(imm => {
      imm.push(new Valutazione());
      console.log('inside', imm);
    }
    );
    this.immobili.subscribe(i => console.log('after', i));
  }

Now it skips completely the map function. The logs 'before' and 'after' shows the same array, and the 'inside log' doesn't show.

Do you want to change whole object or just modify the values of array based on some condition? — Basavaraj Bhusani
– Basavaraj Bhusani, Commented Sep 4, 2017 at 12:51
Only the values of the array, as I'm doing inside the subscribe() call. I need to return an Observable that contains the modified array. — esseara
– esseara, Commented Sep 4, 2017 at 12:54

Sumit Agarwal · Accepted Answer · 2017-09-04 12:56:38Z

1

Instead of subscribing you can use map:

immobili.map(
  imm => { 
    console.log(imm);
    imm.push(new Valutazione());
    console.log(imm);
    this.myImmobili = //some code here
  }
);

answered Sep 4, 2017 at 12:56

Sumit Agarwal

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3 Comments

esseara Over a year ago

I changed my code as you and @Basavaraj Bhusani suggest but it skips completely the map operator execution.

Sumit Agarwal Over a year ago

you need to subscribe atleast once at the end point. You can't use only map. it has to be coupled with subscribe.

esseara Over a year ago

That was it. Thanks.

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