Test your JavaScript Skills:Fundamentals-8

Introduction

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

1. Identify the output of the below program

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

   a.10

   b.undefined

   c.error

   d. NaN

   e.0

   Answer: c

   Reason: Since the variable 'i' is not hoisted, the interpreter yields an error.

2. Identify the output of the below program

    let i=10;
    i=40;
    let i=50;
    console.log("value", i);
   

   a. error

   b.50

   c.40

   d. 10

   e.undefined

   Answer: a

   Reason: Re-declaration using let is invalid.

3. Identify the output of the below program

   
    let i=10;
    if (i>3) {
        let j=20;
    }
    console.log("value", j);
   

   a. 20

   b.10

   c.undefined

   d. NaN

   e.error

   Answer: e

   Reason: Since let has a block scope the variable 'j' is not accessible outside the block.

4. Identify the output of the below program

   
    function fx() {
     let i=10;
        function fx2() {
            console.log("value", i);
        }
        fx2();
    }
    fx();
   

   a.10

   b.error

   c.undefined

   d. NaN

   e.0

   Answer: a

   Reason: In the context of function fx2, the variable is global and hence accessible.

5. Identify the output of the below program

   
    function fx() {
        function fx2() {
            console.log("value", i);
        }
        fx2();
        let i=10;
    }
    fx();
   

   a.undefined

   b.NaN

   c.error

   d. 10

   e.0

   Answer: c

   Reason: Since variable 'i' is not hoisted interpreter yields an error.

6. Identify the output of the below program

   
    try {
        let i=10;
    }catch (e) {
        console.log(e);
    }
   
    console.log("value", i);
   

   a.error

   b.10

   c.undefined

   d. 0

   e.null

   Answer: a

   Reason: Since variable 'i' has a block scope it is not accessible outside the block.

7. Identify the output of the below program

   
    function fx() {
     let i=10;
        if (i>3) {
            let j=20;
        }
        console.log("value", j);
    }
    fx();
   

   a.10

   b.20

   c.NaN

   d. undefined

   e.error

   Answer: e

   Reason: The variable 'j' has a block scope hence not accessible outside 'if' condition.