Rx.Observable.prototype.filter(predicate, [thisArg])

Filters the elements of an observable sequence based on a predicate. This is an alias for the where method.

参数

1. predicate (Function): A function to test each source element for a condition. The callback is called with the following information:
   1. the value of the element
   2. the index of the element
   3. the Observable object being subscribed
2. [thisArg] (Any): Object to use as this when executing the predicate.

返回值

(Observable): An observable sequence that contains elements from the input sequence that satisfy the condition.

例