Test your JavaScript Skills: Fundamentals-11

Introduction

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

1. Identify the output of the below program

    if (null+true)    
        console.log("true"); 
    else
        console.log("false");
   

   a.false

   b.true

   c.error

   d. undefined

   e.null

   Answer: b

   Reason: Here null is coerced to 0 and true to 1 hence 0+1 is 1 which is truthy.

2. Identify the output of the below program

    if ([1,2,3])  
        console.log("true"); 
    else
        console.log("false");
   

   a.false

   b.true

   c.error

   d. undefined

   e.null

   Answer: b

   Reason: An array object is a truthy value.

3. Identify the output of the below program

    function fx() {}    
   
    if (fx)  
        console.log("true");
    else
        console.log("false");
   

   a.null

   b.error

   c.false

   d. undefined

   e.true

   Answer: e

   Reason: A function is an object and an object is a truthy value.

4. Identify the output of the below program

    function fx(){}
   
    if (new fx())  
        console.log("true");
    else
        console.log("false");
   

   a.error

   b.null

   c.undefined

   d. false

   e.true

   Answer: e

   Reason: An object is a truthy value.

5. Identify the output of the below program

    if (new Date())  
        console.log("true"); 
    else
        console.log("false");
   

   a.undefined

   b.error

   c.false

   d. true

   e.date

   Answer: d

   Reason: An object is a truthy value.

6. Identify the output of the below program

    function fx() {}
   
    if (fx())  
        console.log("true"); 
    else
        console.log("false");
   

   a.error

   b.false

   c.true

   d. undefined

   e.0

   Answer: b

   Reason: The function call returns undefined which is falsey.

7. Identify the output of the below program

    if ({name:"Ram"})  
        console.log("true"); 
    else
        console.log("false");
   

   a.undefined

   b.null

   c.true

   d. false

   e.error

   Answer: c

   Reason: An object is a truthy value.