any pictures

I think that you meant to say your hallway is 4' (feet) wide, not 4" (inches) wide.

4 feet is wide enough to have a door swing out into the hallway for a residential project such as yours. Make sure that the door can be fully opened and has a place to swing back against the wall if you want it to be in the open position.

Another option is to put in a barn style door. You can buy the hardware at a store like Lowe's and hang a regular door. The only problem with a barn door is that it does not seal as well as a regular swinging door. If the bathroom is isolated from other rooms and noise privacy is not a problem, then you might consider the barn door.

If the door opening into hallway bothers you try a sliding barn door like mentioned above such as this one:

[Sliding barn door[(https://www.houzz.com/photos/master-bathroom-rustic-bathroom-atlanta-phvw-vp~1942510)

Yes, I did mean 4 feet, not inches.

Neither a barn door or a picket door will work in my location because of wall space and a structural support post. My only options are a regular door opening in or out.

If you don't have wall space for a barn door, then this means your swing out door won't be able to be fully opened and up against the wall........this could be a problem unless you can keep your bathroom door shut all of the time. It sounds like you don't have much choice.....Another option could be a roll up door (like the kind you see on industrial garages.) An odd choice but it could work for you and the grandkids would love it.........

Yes, very few choices. I think the door would have to stay closed all of the time (perhaps not such a bad idea for a bathroom). Thanks for pointing out to me the part of there not being a wall for this to lean open against; I hadn't considered it.

LOL I can just picture a 3 or 4 year old trying to pull a garage door type door up or down.

The shape of the bathroom is like one of those neo-angle showers where one corner is cut off. The door is on one of those short walls adjacent to the cut off wall. The wall where the bathroom is is only about 4' (got it right this time), so that is why there is no space for pocket or barn door.

Thanks a lot!

I have a small powder room and the door opens into the hallway. It hasn't caused any problems. When we renovated a few years ago, we switched it so that the door handle is on the right rather than the left, facing the door. Now we don't have to look at the toilet when the door is partly open, because the partly-open door faces another wall.

Great idea I would never have thought of! Thanks!

I need a visual of the door opening into a hallway

There doesn't seem to be prohibitions for outward opening bathroom doors in the International Residential Code. So, as long as there is clearance and no hazard created would think that it would be ok.