It probably isn't really using that much but it will have reserved that much. V8 reserves memory in chunks of 256MB using virtualalloc with MEM_RESERVE on Windows (I think). It has to do that for each isolated process where an isolate is a tab, webview, worker, etc. A page that's built up from 4 isolated processes will reserve 1GB of RAM. That's only virtual alloc though, so other OS processes can take the memory if they really need it.
There is essentially no way to tell if a JS app is using a lot of memory just by looking at what the process has reserved. There's loads of things that end up in that space - cached pages, cached compiled code, cached bitmaps of rendered pages, etc.
The task monitor tells you what Chrome or Chromium (e.g. Electron) is doing, not what the web app is doing.
There is a good argument to suggest Chromium is hogging more than it should. That's not really WhatsApp's fault though.
I mean, you could argue that you're at fault when you're choosing a platform that literally eats your RAM. They're not at fault that the platform is shit. But they could have chosen another platform. Or, even better, just use the existing, most of the time perfectly working app, and optimize it.
They had no resources to build the new features for every single platform that they offer native clients for?
I could not imagine any other app for which this would be more hypocritical. Give me the iOS WhatsApp IPA from 2016, or even earlier, and the Windows Chromium Wrapper from 2018, and I will tell you neither me nor probably 98% percent of users will notice any difference in feature, let alone design.
There is essentially no way to tell if a JS app is using a lot of memory just by looking at what the process has reserved. There's loads of things that end up in that space - cached pages, cached compiled code, cached bitmaps of rendered pages, etc.
The task monitor tells you what Chrome or Chromium (e.g. Electron) is doing, not what the web app is doing.
There is a good argument to suggest Chromium is hogging more than it should. That's not really WhatsApp's fault though.