Test your JavaScript Skills: Switch Statement - 26

Introduction

Namaste, In this blog I will discuss 10 code scenarios on JavaScript Switch Statement.

1. Identify the output of the below program

    let b="4";
   
    switch(b) {  
        case 4:
            console.log("number");
            break;
        case "4":  
            console.log("string");  
            break;
    }
   

   a. number

   b.string

   c.nothing

   d.error

   e.undefined

   Answer:b

   Reason:The comparison is strict

2. Identify the output of the below program

    let c="4";
    switch(c){ 
      case console.log("JS"):
           console.log("JS2");
           break;
      case console.log("Py"):
           console.log("Py2");
           break;
    }
   

   a. JS,JS2

   b. Py,Py2

   c. JS

   d. Py

   e. JS, Py

   Answer:e

   Reason: Code on the case clause is executed and the returned value is compared which does not match hence next case is compared as well

3. Identify the output of the below program

    let c=8;
    switch(c){ 
      case 8:
           console.log(8);       
      case 9:
           console.log(9);
      default:
        console.log("defualt");
    }
   

   a. error

   b.8

   c.default

   d.8, 9

   e.8,9, default

   Answer:e

   Reason: The cases do not have break hence the control falls through

4. Identify the output of the below program

    let c= undefined;
   
    switch(c) { 
        case undefined:
                console.log("Undefined");
                break;
        case undefined:
                console.log("Undefined2");    
    }
   

   a.Undefined, Undefined2

   b.Undefined

   c.Undefined2

   d.error

   e.nothing

   Answer:b

   Reason: The first matching case is executed

5. Identify the output of the below program

    let c=4;
    switch(c) { 
        case console.log("a"), console.log(c):
            console.log("c");
        default :
            console.log("d");
    }
   

   a.a

   b.a,c

   c.a,4,d

   d.a,d

   e.a,4

   Answer:c

   Reason:The instructions on the case clause are executed. The first case does not match hence default is executed.

6. Identify the output of the below program

    let a=10;
    switch(a) {
        case 1,2:
            console.log("a");
            break;
        case 8,10,9:
            console.log("a2");
            break;
        default:
            console.log("default");        
    }
   

   a.a

   b.a2

   c.default

   d.a2,default

   e.error

   Answer:c

   Reason:None of the case clauses match hence default is executed

7. Identify the output of the below program

    let a=10;
    switch(a) {
        case 8:
        case 10:
        case 8:
            console.log("a");
            break;
        default:
            console.log("default");        
    }
   

   a.default

   b.a

   c.error

   d.nothing

   e.a,default

   Answer:b

   Reason:The 2nd case clause matches.

8. Identify the output of the below program

    function fx() {
        return 3;
    }
   
    let a=1;
    switch(a) {
        case console.log("JS"), fx():
            console.log("case1");
        default:
            console.log("default");
    }
   

   a.JS,case1

   b.JS,default

   c.JS

   d.default

   e.case1

   Answer:b

   Reason: The instructions on the case clause are executed. The first case does not match hence default is executed.

9. Identify the output of the below program

    let a=10;
    switch(a) {
        case 1,2:
            console.log("a");
            break;
        case 8,9,10:
            console.log("a2");
            break;
        default:
            console.log("default");        
    }
   

   a.a

   b.a2

   c.default

   d.a,a2

   e.error

   Answer:b

   Reason:The 2nd case clause matches (the last value)

10. Identify the output of the below program

    let a=10;
    switch(a) {
        case 8:
        case 9:
        case 8:
            console.log("a");
            break;
        default:
            console.log("default");        
    }
    

    a.error

    b.a

    c.default

    d.nothing

    e.a, default

    Answer:c

    Reason: None of the case clause match hence default is executed