56 lines
1.6 KiB
Python
56 lines
1.6 KiB
Python
from asyncio import Future
|
|
from typing import Callable, TypeVar, Union
|
|
|
|
import reactivex
|
|
from reactivex import Observable, abc
|
|
|
|
_T = TypeVar("_T")
|
|
|
|
|
|
def if_then_(
|
|
condition: Callable[[], bool],
|
|
then_source: Union[Observable[_T], "Future[_T]"],
|
|
else_source: Union[None, Observable[_T], "Future[_T]"] = None,
|
|
) -> Observable[_T]:
|
|
"""Determines whether an observable collection contains values.
|
|
|
|
Example:
|
|
1 - res = reactivex.if_then(condition, obs1)
|
|
2 - res = reactivex.if_then(condition, obs1, obs2)
|
|
|
|
Args:
|
|
condition: The condition which determines if the then_source or
|
|
else_source will be run.
|
|
then_source: The observable sequence or Promise that
|
|
will be run if the condition function returns true.
|
|
else_source: [Optional] The observable sequence or
|
|
Promise that will be run if the condition function returns
|
|
False. If this is not provided, it defaults to
|
|
reactivex.empty
|
|
|
|
Returns:
|
|
An observable sequence which is either the then_source or
|
|
else_source.
|
|
"""
|
|
|
|
else_source_: Union[Observable[_T], "Future[_T]"] = else_source or reactivex.empty()
|
|
|
|
then_source = (
|
|
reactivex.from_future(then_source)
|
|
if isinstance(then_source, Future)
|
|
else then_source
|
|
)
|
|
else_source_ = (
|
|
reactivex.from_future(else_source_)
|
|
if isinstance(else_source_, Future)
|
|
else else_source_
|
|
)
|
|
|
|
def factory(_: abc.SchedulerBase) -> Union[Observable[_T], "Future[_T]"]:
|
|
return then_source if condition() else else_source_
|
|
|
|
return reactivex.defer(factory)
|
|
|
|
|
|
__all__ = ["if_then_"]
|