I'd argue we should strive to move away from the switch syntax where it's not necessary because it's verbose and has curious semantics [1]. As an example, this should work:

  switch(expr) {
    case 'foo':
      console.log("a string")
      break;
    case { foo: bar }:
      console.log("foo is", bar)
      break;
  }

But how would this work?

  switch(expr) {
    case 'foo':
    case { foo: bar }:
      console.log("foo is", bar)
      break;
  }

Moreover, a big selling point of pattern matching is it is an expression. Keep in mind though case points to a statement list, How do we resolve to a value?

With a "return"?

  function f() {
    switch(expr) {
      case 'foo':
        return 4 // This makes f return 
    }
  }

  function g() {
    var x = switch(expr) {
      case 'foo':
        return 4 // But this doesn't. Is this confusing?
    }
  }

The value of the last statement?

  function g() {
    var x = switch(expr) {
      case 'foo':
        4; // This should resolve to 4
        break; // but is the break necessary now? 
    }
  }

IMO switch sytnax is just legacy left behind by C, and not the best one to keep around, especially given the semantics of pattern matching.

[1]: https://en.wikipedia.org/wiki/Duff%27s_device, not sure if this works on JavaScript (I doubt it), but the point is the switch cases essentially work like "goto"s.

You'll need to insert a newline and 2 spaces before a code block to be recognized as such:

    switch(expr) {
       case 'foo': break;
       case { foo: bar }: break; 
    }

https://news.ycombinator.com/formatdoc

Ah, thanks. I should have guessed it would work something like that.