How to force Github to build a Gulp project?

Question

C++ / C#

Hello. I have already come across sites on github.io hosting many times, which do not contain connected files and folders in the repository, but they are created via build.
Here is an example of a repository folder:
and At the same time, the site works with a link like ****** .
github.io/****/index.html"
How to force github to build the assembly itself? from another branch.

Answer 1

No need to force GitHub to do what it can't do )
Github as hosting
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