I’m new to ionic and angular also. Is there a fail over mechanism, when a POST/PUT/DELETE request is not successful. We are not developing desktop application, we can not guarantee that the network connection of the device is always available. If not do I have to implement that by myself?
Correct you do have to implement the offline-first functionality yourself. There are many different methods of doing this.
A common and easy method is PouchDB, it allows you to sync data between the device and the server automatically. You can also use local storage and such to hold information, and when the connection becomes available then you can submit the changes to the server. There are a lot of resources, please use the search to find more of how to do this, it’s covered a lot