Switch method : why is num giving me 'num is unknown'?

Question

function testNum(a) {
  switch (a) {
    case a > 0:
      alert("positif num");
      break;
    case a < 0:
      alert("num is negative");
      break;
    default:
      alert("num is unknown");
  }
}

testNum(4);

So im trying to do this simple if statement with Swtich methods and smh simply not working the way i want,why its not giving me 'num is positive' , ???

The case expressions are evaluated, and then `a` is *compared* to the resulting values. 4 is not equal to `true`. — Pointy, Oct 20 '20 at 14:21
You should be using an `if` statement not a `switch` statement — doublesharp, Oct 20 '20 at 14:23
yeah i know i could use if statement,i want to know how to it with switch,thx guys — studmuffin 30, Oct 20 '20 at 14:47

score 2 · Accepted Answer · answered Oct 20 '20 at 14:25

Switch in javascript evaluate an expression and not a number ... The common workaround is to use

 switch(true){

 }

see below :

function testNum(a) {
  switch (true) {
    case a > 0:
      alert("positif num");
      break;
    case a < 0:
      alert("num is negative");
      break;
    default:
      alert("num is unknown");
  }
}

testNum(4);

score 0 · Answer 2 · answered Oct 20 '20 at 14:34

you can't use condition in case use If or this way

function testNum(a) {
  switch (true) {
    case a > 0:
      alert("positif num");
      break;
    case a < 0:
      alert("num is negative");
      break;
    default:
      alert("num is unknown");
  }
}

testNum(4)

Switch method : why is num giving me 'num is unknown'?

2 Answers2