JS Fundamentals - Switch

Question 1

Rules are similar to java

Answer 1

-

Question 2

Expression

Answer 2

Any expression can be a switch/case argument

Both switch and case allow arbitrary expressions.

Question 3

Grouping of “case”

Answer 3

Several variants of case which share the same code can be grouped.

For example, if we want the same code to run for case 3 and case 5

Question 4

Type matters

Answer 4

let arg = prompt("Enter a value?");
switch (arg) {
  case '0':
  case '1':
    alert( 'One or zero' );
    break;

case ‘2’:
alert( ‘Two’ );
break;

  case 3:
    alert( 'Never executes!' );
    break;
  default:
    alert( 'An unknown value' );
}

For 0, 1, the first alert runs.
For 2 the second alert runs.
But for 3, the result of the prompt is a string “3”, which is not strictly equal === to the number 3. So we’ve got a dead code in case 3! The default variant will execute.