Javascript scope variable to switch case?

Question

In C you can scope a variable to a switch case, like this.

With javascript I get unexpected token using the following:

const i = 1    switch (i) {      // variables scoped to switch      var s      var x = 2342      case 0:        s = 1 + x        break      case 1:        s = 'b'        break  }

Is there another way to do this or should I just declare my variables outside the switch?

EDIT:

This is a workaround I considered but it didn't end up working. The reason being that each case has its own scope.

const i = 1    switch (i) {      case i:        // variables scoped to switch        var s        var x = 2342      case 0:        s = 1 + x        break      case 1:        s = 'b'        break  }

Answer 1

some alternative:

/* curly braces inside the case */  const i = 1  switch (i) {   case 0: {     let x = 2342;     let s = 1 + x;     console.log(x+' & '+s+' from inside');   } break;   case 1: {     let x = 2342;     let s = 'b';     console.log(x+' & '+s+' from inside'); /* 2342 & b from inside */   } break; }  console.log(x+' & '+s+' from outside'); /* Uncaught ReferenceError */ 

or

/* curly braces outside the switch */  const i = 1  {   let x = 2342;   let s;   switch (i) {     case 0:       s = 1 + x;       break;     case 1:       s = 'b';       break;   }   console.log(x+' & '+s+' from inside'); /* 2342 & b from inside */ }  console.log(x+' & '+s+' from outside'); /* Uncaught ReferenceError */ 

Answer 2

Since var creates variables at function scope anyway, using it is pretty pointless. For this to work at a granularity below function scopes you'll have to use let and a browser/compiler which supports it, and then introduce a new block which you can scope things to (within switch it's simply invalid syntax):

if (true) {     let s;      switch (i) {         ...     } } 

This scopes s to the if block, which for all intents and purposes is identical to the "switch scope" here.

If you cannot support let, you'll need to use an IIFE:

(function () {     var s;      switch (...) ... })();