JAVASCRIPT

switch case block scope

let number  = 2;

switch (number) {
    case 1: 
        let message = "first number";
        console.log(message)
        break;
    case 2:
        let message = "second number";
        console.log(message)
        break;
  case 3:
        let message = "third number";
        console.log(message)
        break;
    default
        let message = "second number";
        console.log(message)
        break;
}

//This throws a syntax error: identifier "message" 
//has already been declared

//Here is a way to fix this issue:

let number  = 2;

switch (number) {
    case 1: { // braces make the case statement a block
        let message = "number" + number; // this remains in this block
        console.log(message)
        break;
    }
    case 2: {
        let message =  "number" + number; // this is a valid syntax
        console.log(message)
        break;
    }
    case 3: {
        let message = "number" + number; 
        console.log(message)
        break;
    }
    default
        let message =  "number" + number;
        console.log(message)
        break;
}