Test your JavaScript Skills:Fundamentals-12

Introduction

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

1. Identify the output of the below program

    let mydata= -123.123;
   
    if (mydata)  
        console.log("true");
    else
        console.log("false");
   

   a.false

   b.true

   c.undefined

   d. null

   e.error

   Answer: b

   Reason: A non-zero number is truthy.

2. Identify the output of the below program

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

   a.false

   b.true

   c.error

   d. undefined

   e.null

   Answer: a

   Reason: The function returns undefined as a value which is a falsey value.

3. Identify the output of the below program

    function fx3() {
        let i = 0/10;
        return i; 
    }
   
    if (fx3())
     console.log("true");
    else
      console.log("false");
   

   a.error

   b.undefined

   c.false

   d. true

   e.null

   Answer: c

   Reason: The function returns 0 which is a falsey value.

4. Identify the output of the below program

    let j = Infinity/Infinity;
    console.log("value", j);
   

   a.Infinity

   b.null

   c.1

   d. NaN

   e.error

   Answer: d

   Reason: The Infinity/Infinity yields into NaN in Javascript.

5. Identify the output of the below program

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

   a.error

   b.undefined

   c.error

   d. false

   e.true

   Answer: d

   Reason: Empty string is a falsey value.

6. Identify the output of the below program

    function fx4() {
        let i = Infinity/Infinity;
        return i; 
    }
    if (fx4())
     console.log("true");
    else
      console.log("false");
   

   a.true

   b.false

   c.error

   d. NaN

   e.undefined

   Answer:b

   Reason: The function returns NaN which is a falsey value.

7. Identify the output of the below program

    function fx2() {
        let i = 1/0;
        return i; 
    }
    if (fx2())
     console.log("true"); 
    else
      console.log("false");
   

   a.false

   b.true

   c.undefined

   d. null

   e.error

   Answer:b

   Reason: The function returns Infinity which is a truthy value.