Test your JavaScript Skills:Fundamentals-18

Introduction

Namaste, In this blog I will discuss 7 code scenarios on Javascript fundamentals.

1. Identify the output of the below program

    class mycls{}
    var mycls=2;  
    console.log("type", typeof mycls);
   

   a.2

   b.class mycls{}

   c.function

   d.error

   e.undefined

   Answer: d

   Reason: Because of re-declaration there is an error.

2. Identify the output of the below program

    function fx(){}
    class fx{}
    console.log("type", typeof fx);
   

   a. function

   b.class

   c.undefined

   d.number

   e.error

   Answer: e

   Reason: Because of re-declaration there is an error.

3. Identify the output of the below program

   
    function fx() { console.log("fx");}
    function fx() { console.log("fx-2");}
    fx();
   

   a.fx

   b.fx-2

   c.error

   d.no-output

   e.null

   Answer:b

   Reason: Since fx is hoisted there is no error.

4. Identify the output of the below program

    console.log("value", i); 
    i=10;
   

   a.10

   b.undefined

   c.error

   d.null

   e.no-output

   Answer:c

   Reason: The variable is not hoisted.

5. Identify the output of the below program

    console.log(typeof console);
   

   a.null

   b.class

   c.function

   d.object

   e.string

   Answer:d

   Reason: The typeof of 'console' is object.

6. Identify the output of the below program

    if ( 10 > (let i=3)) {
        i=11;
    }else {
        i=10;
    }
    console.log("value", i);
   

   a. 3

   b.11

   c.10

   d.undefined

   e.error

   Answer: e

   Reason: Invalid syntax i.e. declaration of 'i' is invalid.

7. Identify the output of the below program

    fx()
    function fx() {
     console.log("fx");
    }
   

   a.fx

   b.error

   c.undefined

   d.null

   e.no-output

   Answer: a

   Reason: Function fx is hoisted.