Although JS doesn’t allow picking up files willy-nilly from a user’s local system, we could definitely ask permission from the user to do so. The way I found to do this is by asking the user to fill a file input field which will contain the JSON data we want to read.
Problem is we will have to ask the user to navigate to the file and this would be a great hurdle to the usability of the application. But, having a very small amount of time left for the project and having built almost all of the application in JS already, I will have to pursue this way even if it isn’t the most efficient one.