Change Frontend Responses to use Classes

[mfish33]

Currently, the frontend uses a reactive system to alert different parts of the frontend about editor changes. In order to do this, all responses are described by interfaces and have a corresponding new function.

export interface SaveDocument {
	document: string;
	name: string;
}
function newSaveDocument(input: any): SaveDocument {
	return {
		document: input.document,
		name: input.name,
	};
}

Switching to a class-based system would have various benefits

• Classes stay in after compilation. This would allow us to offer better type checking on the main subscription API

function registerResponseHandler(responseType: ResponseType, callback: ResponseCallback)

to

function subscribeJsMessage<T extends JsMessage>(responseType: Constructs<T>, callback: JsMessageCallback<T>)

The advantage of this change is that the callback given to subscribeJsMessage automatically has the correct type for the input parameter and does not need to be cast. Removing this cuts down on boilerplate code where mistakes can be made.

• The other advantage of a class-based system is we can remove the new function to create a given type. Instead, we can make use of a library class-transformer in order to automate this process, further cutting down on code duplication.

• Finally while implementing the class solution, naming should be refactored to better align with the backend message system