JavaScript in VS Code: why can't I collapse the 'case' code blocks in my 'switch' statements?

You can fold switch statements in vscode by clicking the minus side near the line number of where the switch statement starts. Here is an example of what I mean

The issue I think you are having is that your Folding strategy is set to auto. If you set it to indentation then it should work for the case blocks. Try setting this in your preferences:

"editor.foldingStrategy": "indentation"