# filter | where

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

## Arguments

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.

## Returns

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

## Example
