Observable finally not getting fired

Question

This works:

this.http.get('/doesntexist1')
  .finally(() => console.log('finally1'))
  .subscribe(() => { });

But this doesn't:

const obs = this.http.get('/doesntexist2');
obs.finally(() => console.log('finally2'))
obs.subscribe(() => { });

Both URL produce a 404.

I run both and I only see "finally1" being displayed in the console, any idea why?

Answer 1

The difference is that in the second example the .finally is not in the same stream as the .subscribe since you aren't chaining them.

Your first example creates this stream:

get -> finally -> subscribe

Your second example creates two branches:

get -> finally
get -> subscribe

The finally wont be executed without a subscription after it.

If you want to build a stream then you need to chain the operators by using the result of the previous operator. It isn't like an in-place operator.