Test your JavaScript Skills:Fundamental-22

Introduction

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

1. Identify the output of the below program

    let x=1;
    (x>2) && console.log("first"); console.log("second");
   

   a.first

   b.second

   c.no output

   d.error

   e.undefined

   Answer:b

   Reason: The condition is false and the 2nd console.log is not part of the expression hence "second" is printed.

2. Identify the output of the below program

    0;
    1;
    console.log("2");
   

   a.0

   b.1

   c.2

   d.error

   e.undefined

   Answer:c

   Reason: The program is syntactically correct hence 2 is printed.

3. Identify the output of the below program

    x=1;
    (x>2) && console.log("first") || console.log("second");
   

   a.first

   b.1

   c.2

   d.second

   e.error

   Answer: d

   Reason: The first expression of the || operator is falsey hence the second expression is taken, and therefore "second" is printed.

4. Identify the output of the below program

    function fx() {
        return 10;
    }
   
    function fx2() {
        return 20;
    }
   
    console.log(fx() && fx2());
   

   a.1

   b.undefined

   c.error

   d.20

   e.10

   Answer:d

   Reason: Both the functions return truthy values and since && is used the last value is taken which is 20.

5. Identify the output of the below program

    let a = +"3";
    console.log (typeof a);
   

   a.string

   b.number

   c.NaN

   d.undefined

   e.null

   Answer:b

   Reason: The string is coerced into a number.

6. Identify the output of the below program

    x=10;
    (x>2) && console.log("first") || console.log("second");
   

   a.first

   b.second

   c.10

   d.2

   e.error

   Answer:b

   Reason: The first expression of the || operator is falsey hence the second expression is taken, and therefore "second" is printed.

7. Identify the output of the below program

    function fx() {
        return 10;
    }
   
    function fx2() {
        return 20;
    }
   
    console.log(fx() || fx2());
   

   a.10

   b.20

   c.0

   d.error

   e.undefined

   Answer: a

   Reason: The call to fx() returns truthy value hence 10 is printed.