How to load the page only when a request comes from the server?

Question

Express.js

I have a website and when I update a page or access it, a GET request goes to the server, the server sends a request to the database and the data is shown on the website as cards, but the Pages loaded and only after some time these cards appeared, because you need to wait for the request. The question is how to make the page load only when the request has already arrived, but for now how the page has not loaded, show the loader in the middle of the screen, like many sites?

Answer 1

1. flag variableisLoaded = false
   
2. If isLoaded === false- turn the preloader
   
3. Sending a request
   
4. Request ends
   
5. flag variableisLoaded = true
   
6. If isLoaded === true- hide preloader and show content