I am looking for solutions able to make the sign-in and sign-up functions or flow into a component or a module or something that can be used by mobile apps and web apps. Why? Inside an organization, we have many apps requiring the same sign-in and sign-up functions. Currently, it is app developers crafting the UI and also calling the APIs of sign-in and sign-up. The similar codes handling sign-in and sign-up are obviously scattered across projects. The worst is when we want to add, Google Auth, for example, apps require Google Auth must again change or refactor their apps which at the same time the change on backend side is needed as well.
I read a bit solutions like IBM Worklight or similar ideas like React Native pitch about development one time and deployment onto multiple platforms. Except for using off-the-shelf technologies, what is the best practice or suggestion intending to achieve a similar purpose? Or, any real example? Or, this is actually a bad idea for a universal login module?