1. The law does not clearly provide for this;
2. The only principle is that you must not obstruct the passage of others or infringe on the legitimate rights and interests of others;
3. If the areas involved are owned by the same owner both internally and externally, there will be no infringement issues involved.
Under normal circumstances, most doors open inward. This involves an issue of whether there is infringement. If it opens to the outside, it is likely that the ownership of the area involved is not owned by the unit. From a Feng Shui perspective, if you open it inward, you will gather wealth from all directions, while if you open it outward, all the gold will be dispersed.