Javascript Introduction
Comments in Javascript
Javascript Variables
Difference between var, let and const in Javascript
Datatypes
Assignment Operators
Logical Operators
Comparison Operators
Actions alert, prompt & confirm

Javascript Flow Control
Conditional Statements in Javascript
Nullish coalescing operator in Javascript
Break and Continue in Javascript
Loops in javascript
for loop in Javascript
while loop

Javascript Functions
Javascript Functions
JavaScript Arrow Function

Javascript Objects
Javascript Objects

Javascript Array
Javascript Arrays

Javascript Error Handling
Error Handling in Javascript

Javascript ES6
Set
Javascript Spread Operator
Rest Parameter in Javascript

Javascript Asynchronous
Javascript Callback Function
Promises in Javascript
Promise Chaining
Async-Await in Javascript

Javascript DOM
DOM Document
DOM Elements
DOM Attributes
DOM Manipulation
DOM Node Lists
Javascript Events
DOM Traversing Elements
DOM EventListener

Javascript Class
Classes in javascript
Class Inheritance

Javascript Design Principles
SOLID - The Single responsibility principle in javascript
SOLID - Open-Closed principle in Javascript

Other Topics
Javascript Hoisting
Filter, Map and Reduce functions in Javascript
Closure in Javascript
Optional chaining operator in Javascript
Consoling in table format in javascript
Fetch API in Javascript
HTML web Storage API
Checking the online or offline status of the browser

Conditional Statements in Javascript

Published on: July 03, 2021 By T.Andrew Rayan

The conditional statements in javascript is used to execute set of statements based on condition.

To perform conditional check we use the following statements:

*) if statement

*) if-else statement

*) else-if statement

*) switch statement

if statement:

The if statement is used to execute a block of codes if the condition is true.

Syntax of if statement:

    
if(condition) {
 // block of codes.
}

Example for if statement:

    
let gender = "male";
if(gender === "male"){
  console.log("Good morning Sir");
}

This will display "Good morning Sir" as output to the console.

if-else statement:

The if-else statement acts like a switch. It executes a block of codes in if statement, if the condition is true. If the condition is not satisfied then it will execute the block of codes in the else statement.

Syntax for if-else statement:

    
if(condition){
 // block of codes
} else {
 // block of codes
}

Example for if-else statement:

    
let gender = "female";
if(gender === "male"){
  console.log("Good morning Sir");
} else {
  console.log("Good morning Madam");
}


  

This will display "Good morning Madam" as output to the console.

else-if statement:

If there is a scenario to check more than 2 conditions then we need to go for else-if statement.

Syntax for else-if statement:

    
if(condition){
// block of codes
} else if(condition){
// block of codes
} else {
 // default block of codes
}


  

Example for else-if statements:

    
let hour = 13;
if(hour > 12) {
  console.log("Good morning");
} else if(hour > 12 && hour < 16) {
  console.log("Good afternoon");
} else if(hour > 16 && hour < 24) {
  console.log("Good evening");
} else {
  console.log("Good day");
}


  

On executing this program it will display Good afternoon. Here we have checked 3 conditions and if any of the 3 condition is not satisfied then the else statement will be executed.

Here we have multiple conditions, so instead of going for else-if statement, we can prefer using the switch statement.

switch statement:

The switch statement can be used to check multiple condition and select any one of the condition to be executed. If no condition is satisfied, then it will execute the codes in the default block.

Syntax for switch statement:

    
switch(expression) {
 case value1:
  // block of codes
 break;
 case value2:
  // block of codes
 break;
 case value3:
  // block of codes
 break;
 default:
  // block of codes
 break;
}


  

Example for switch statement:

    
let code = 2;
switch(code) {
   case 1:
	console.log("One");
   break;
   case 2:
	console.log("Two");
   break;
   case 3:
	console.log("Three");
   break;
   default:
	console.log("Option not valid");
   break;
}


  

The switch statement can contain multiple case statements. Each statements have a set of codes. Once the codes are executed, we use break keyword to break from rest of the condition check.

So we can be assured that only one condition is executed inside a switch statement. If any of the conditions is not satisfied, then it will execute the block of codes in the default code block.

Conditional Statements in Javascript

Published on: July 03, 2021 By T.Andrew Rayan

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