问题
With RxJs, once we start subscribe to an observable, we will start getting values once they are emitted, but how do I get all the values emitted by an observable before I've subscribed to it?
回答1:
An observable is just a function that returns 0 or more values between now and the end of time. Like any other function it doesn't do anything before it's called (subscribed to).
That being said, you can transform your observable to a hot observable by calling:
// This makes the observable 'connectable'
myObservable.publish();
// And make it start emitting items
myObservable.connect();
Alternatively, if you create the observable from say an array, you could ofcourse just look at the array :)
来源：https://stackoverflow.com/questions/41281879/rxjs-how-to-get-values-emitted-before-we-subscribe