How do you redeclare variables in a switch block without an error

When you try to redeclare variables using let or const in multiple case clauses of a switch statement, you will get a SyntaxError. This happens because, in JavaScript, all case clauses within a switch statement share the same block scope. For example:

let counter = 1;
switch (x) {
  case 0:
    let name;
    break;
  case 1:
    let name; // SyntaxError: Identifier 'name' has already been declared
    break;
}

To avoid this error, you can create a new block scope within each case clause by wrapping the code in curly braces {}. This way, each let or const declaration is scoped only to that block, and redeclaration errors are avoided:

let counter = 1;
switch (x) {
  case 0: {
    let name;
    // code for case 0
    break;
  }
  case 1: {
    let name; // No SyntaxError
    // code for case 1
    break;
  }
}

That means, to safely redeclare variables in different cases of a switch statement, wrap each case’s code in its own block using curly braces. This ensures each variable declaration is scoped to its specific case block.