How to avoid Removing Existing Functions when publishing new functions under azure functionapp using terraform

Hi All,
Hope all are doing good.
I am facing an issue related to azure functions, when i deploy new functions under functionapp existing functions are deleted and only new functions are displayed.

Using Visual studio we can fix this issue but i would like to fix this issue using terraform. If anybody have any idea or solution please share and help me.

Thanks in advance.

Regards,
Ajay