How are Objects with Functions Handled in Node.js?

I am currently using Node.js to handle the back-end of my website but I am unsure of how Websockets/Objects are handled together. This is a template I am using as an example of my main class. (Sends web-requests to a specific page) } This is my Main Websocket File (Stripped for simplicity) Lets say I receive data from the WebSocket and that data creates a new ViewClass object and starts running immediately. Will that Now Running code block the input/output of the Node.js Server? Or will it be handled in the background? If there is any information I can provide