New object is created everytime the server refreshes thus unable to edit the data

I have a class blockchain defined in js and I am creating its object within the same file. The moment I run the server the object gets created and I can execute my rest of the functions but if I am trying to edit the data in blockchain using a function the server refreshes again and thus creating new object every time, therefore initializing the blockchain every time. How can I address this?enter image description here