Test your JavaScript Skills:Fundamentals-7

Introduction

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

Identify the output of the below program
```
 function fx() {
     for (var i=0; i< 3;) {
         i++;
     }
  console.log("value", i);
 }
 fx();
```
a.3

b.4

c.NaN

d. undefined

e.error

Answer: a

Reason: Since var does not have block scope it can be accessed outside for loop.
Identify the output of the below program
```
 function fx() {
     for (var i=0; i< 3;) {
         i++;
     }

 }
 fx();
 console.log("value", i);
```
a.3

b.4

c.error

d. undefined

e.NaN

Answer: c

Reason: The scope of 'var' is limited to function fx hence cannot be accessed outside the function.

Identify the output of the below program

 function fx() {
     var i=10;
     console.log("value", j);
     if (i > 3)
       var j=5;

 }
 fx();

a.error

b.5

c.3

d. NaN

e.undefined

Answer: e

Reason: The variable 'j' is hoisted.

Identify the output of the below program
```
 function fx() {
     var i=10;
     console.log("value", j);
     if (i > 32)
       var j=5;

 }
 fx();
```
a.5

b.10

c.error

d. undefined

e.NaN

Answer: d

Reason: The variable 'j' is hoisted hence it is undefined. It should be noted that the condition (i>32) is false still the hoisting still happens.
Identify the output of the below program
```
 try {
  var i=10;
 }catch (e) {
     console.log("catch");
 }

 console.log("value", i);
```
a.error

b.10

c.undefined

d. NaN

e.0

Answer: b

Reason: The 'var' does not have a block scope and hence can be accessed outside.
Identify the output of the below program
```
 function fx2() {
     var data=102;     
      function fx3() {
          console.log("value",data); 
      }
      fx3();
 }

 fx2();
```
a.102

b.error

c.undefined

d. NaN

e.null

Answer: a

Reason: Since variable 'data' is global in the context of function fx3 it can be accessed inside function fx3.

Identify the output of the below program

 function fx2() {    
      function fx3() {
          console.log("value",data); 
      }
      fx3();
      var data=102;
 }
 fx2();

a.102

b.error

c.undefined

d. null

e.NaN

Answer: c

Reason: The variable is hoisted hence it is accessible inside function fx3.