Test your JavaScript Skills:Fundamentals-19

Introduction

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

1. Identify the output of the below program

    cls = 10;
    class cls {}
    console.log(typeof cls);
   

   a.number

   b.function

   c.class cls{}

   d.error

   e.10

   Answer:d

   Reason: The error is - cannot access 'cls' before initialization.

2. Identify the output of the below program

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

   a.error

   b.10

   c.undefined

   d.null

   e.no output

   Answer:b

   Reason: The variable 'i' is module level and hence is accessible.

3. Identify the output of the below program

    var j=9;
    if (j>10)
     i=35;
   
    console.log("value",i);
   

   a.error

   b.9

   c.35

   d.undefined

   e.no output

   Answer: a

   Reason: The variable 'i' is not defined hence the error.

4. Identify the output of the below program

    console.log(typeof console.log);
   

   a.object

   b.function

   c.class

   d.string

   e.undefined

   Answer:b

   Reason: The typeof console.log is a function.

5. Identify the output of the below program

    var j=11;
    if (j>10)
     i=35;
   
    console.log("value",i);
   

   a.11

   b.35

   c.undefined

   d.error

   e.no-output

   Answer:b

   Reason: Since the condition is true, the variable 'i' is initialized. Since variable 'i' is module level can be accessed outside the 'if' block.

6. Identify the output of the below program

    if (10 > (i=3)){
        console.log("true"); 
    } else {
        console.log("false"); 
    }
   

   a.true

   b.false

   c.error

   d.undefined

   e.no output

   Answer: a

   Reason: The condition is true hence 'true' is printed.

7. Identify the output of the below program

    console.log(typeof console.log());
   

   a.number

   b.undefined

   c.function

   d.object

   e.error

   Answer: b

   Reason: The call to console.log() returns nothing hence the result is undefined.