NgRedux + Angular +选择在订阅时触发

Question

I'm using redux in my angular App for weeks now, but I just noticed something about it :

When I'm selecting a part of my store to monitor changes, let's say like that :

In the ngOnInit() of app.component.ts

this.ngRedux.select(s => s.counter).subscribe((counter: number) => {
    console.log(counter)
});

The console.log(counter) is executed each time my counter value change, that's ok, that's how it suppose to works.

BUT, the callback is also executed when I first subscribe. So it's like that :

1. Enter onNgInit()
2. Executing select()
3. Executing Subscribe()
4. Executing my callback
5. ------- Later when counter change : -------
6. Executing my callback

My problem is that I dont want my callback to be executed on step 4, because the store did not change !

Is there an issue in my understanding ? Is is supposed to work like that ? If yes : Can I do something to change it ?

Thanks

Answer 1

Unfortunately, this is the standard behaviour of .subscribe() . The only thing you can do is to compare your current value of counter with the new one and only react on it if changes happened.