When switch case, concatenate the error case and if of the conventional judgment expression and use L

let a = 5
let b = 6
switch (a) {
    
  case 3:
    console.log('a by 3');
    break;
  case 4:
    console.log('a by 4');
    break;
  case (5 && b === 6):
    console.log('a by 5 And b by 6');
    break;
  case 5:
    console.log('a by 5'); // Output  
    break;
}

Imagine the situation ： Output a by 5 And b by 6
Physical truth ：case Back ： Is to associate an expression with switch The latter value is compared with it to get a true or false.
First, we calculate this expression 5 && b === 6// yes true,5 The Boolean value is true and a === true yes false
It can be written.

let a = 5
let b = 6
switch (a) {
    
  case 3:
    console.log('a by 3');
    break;
  case 4:
    console.log('a by 4');
    break;
  case 5:
    if (b === 6) {
    
      console.log('a by 5 And b by 6');
    }
    break;
  case 5:
    console.log('a by 5'); // Output  
    break;
}