CODEWITHSUNDEEP
javascriptrxjsrxjs5
softshipper
softshipper

Reputation: 34099

Why connectable observable get execute only once

I have a connectable observable that will get connected, when the other stream executed:

const source1 = Rx.Observable.of([1,2,3,4,5])
  .do(() => console.log('Do Something!'))
  .map(() => "Always connected.")
  .publish();

source1.subscribe((v) => console.log(v));

const connect = () => {
  let c = false;
  return () => {
    if (!c) {
       console.log("Get connected");
       source1.connect();
       c = true;
    }
  }
}


const source2 = Rx.Observable.fromEvent(document, 'click')
   .do(() => console.log("execute!"))
   .do(connect())
   .switchMapTo(source1);

source2.subscribe((v) => console.log(v));

The output

"execute!"
"Get connected"
"Do Something!"
"Always connected."

Further clicks on the document source1 will be not subscribe anymore and my question is, why?

Upvotes: 2

Views: 293

Answers (1)

martin
martin

Reputation: 96949

You've encountered exactly this situations: Rx.Subject loses events

If you update the first part of your example you'll see that the Subject receives a complete notification:

const source1 = Rx.Observable.of([1,2,3,4,5])
  .do(() => console.log('Do Something!'), null, () => console.log('source1 complete'))
  .map(() => "Always connected.")
  .publish();

This marks that Subject as closed and it won't reemit any values ant further.

See my linked answer above for more detailed information. Also you might have a look at On The Subject Of Subjects (in RxJS) (paragramp Subjects Are Not Reusable) by Ben Leash (lead developer of RxJS 5.

Upvotes: 1

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