I know I can share connector among many processes but I am curious can I reuse Message shape in another process or Map shape does it consider to be a best practice sharing these two shapes
Yes, you can reuse both the Message Shape and the Map Shape.
The Message shape is saved along with the process as an completely independant object. That means if you copy the message shape from one process to another and then changes it in the first process, then it will not change in the second process.
The Map Shape is reusable, but if you change it inside one process it will also change in all other processes that uses this component. So when dealing with "global" map shapes used in different processes, you must be very careful when changing something.
I don't know what best practice would be, but I do normally not reuse map shapes in different processes. If I did, I know for sure that at some point in the future I would be asked to change something in a process and forget everything about it is being used in another process.
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