Check for a switch case with null value in javascript

Question

I have written the below code.

  if(result === ""){
      show("Something went wrong!!");
  }
  else if (result === "getID") {
      show("success");
  }
  else {
     doSomething();
  }

How can I write this using a switch case statement in JavaScript. I'm not sure how can I check for a null value in a switch case condition.

Could someone help me on this??

Answer 1

In this example, it doesn't matter if result is null or "", control will reach console.log("Something went wrong");

switch (result) {
    case null:
    case "":
        console.log("Something went wrong");
        break;
    case "getID":
        console.log("Success");
        break;
    default:
        console.log("doSomething");
}

Answer 2

A switch will catch all the falsy values separately. These values include undefined, null, false, 0, and ''.

An if statement will report all as false.

A snippet is worth 1000 words...

const input = [null, undefined, '', false, 0]

console.log('switch results')
input.forEach(result => {
  switch (result) {
    case false:
      console.log("false");
      break;
    case "":
      console.log("empty string");
      break;
    case null:
      console.log("null");
      break;
    case undefined:
      console.log("undefined");
      break;
    case 0:
      console.log("0");
      break;
    default:
      console.log("default");
  }
})

console.log('if results')
input.forEach(result => {
  if (!result) {
    console.log(result + ' is false')
  } else {
    console.log(result + ' is true')
  }
})