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JavaScript Conditional Statements: if, if else, if else if, switch case

rahxuls profile image Rahul Originally published at rahulism.tech ・2 min read

In this latest post, we will discuss what are conditional statements in JavaScript. These statements are a bit confusing when coding, we'll learn this in a very simple way.


JavaScript supports conditional statements which are used to perform different actions based on different conditions.

Two types of Conditonal Statements:

  • if...else (Has various forms)
    • if statement
    • if...else statement
    • if...else if statement
  • switch...case

General syntax for if...else statement:

if (condition1) {
    statement
} else if {
    statement2
} else {
    statement3
}
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The if a statement executes a statement if a specified condition is true. If the condition is false, another statement can be executed.

  • if statements: if a condition is true, it executes a specific block of code.
  • else statements: if the same condition is false, it executes a specific block of code.
  • else if: this specifies a new test if the first condition is false.

EXAMPLE: To check if a number is positive or, negative or zero.

if (a > 0) {
    var result = "positive"; 
} else if (a === 0 ) {
    var result = "zero"; 
} else {
    var result = "negative"; 
}

// If a = 10 returns positive
// if a = 0 returns zero
// if a = -9 returns negative
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Switch case

(Src: FCC) A switch statement tests a value and can have many case statements which define various possible values. Statements are executed from the first matched case value until a break is encountered.

switch(expression) {
  case x:
    // code block
    break;
  case y:
    // code block
    break;
  default:
    // code block
}
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  • expression : An expression whose result is matched against each case clause
  • case valueN (optional) : A case clause used to match against expression. If the expression matches the specified valueN, the statements inside the case clause are executed until either the end of the switch statement or a break.
  • default : A default clause; if provided, this clause is executed if the value of expression doesn't match any of the case clauses.

EXAMPLE:

function name(val) {
  var answer = "";
  switch(val) {
    case 1:
     return "Rahul"; 
     break; 
    case 2:
     return "Sam"; 
     break; 
    case 3: 
     return "John"; 
     break; 
    case 4: 
     return "Chris"; 
     break;    

  }
  return answer;
}

name(1);

// if val = 1, returns "Rahul". 
// if val = 2, returns "Sam", 
// if val is empty then returns ""

Simple to understand!
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Extra tip by Olver:


originally at -> https://rahulism.tech/article/conditional-statements-in-javascript/


😊Thanks For Reading | Happy Coding 😁

Discussion (7)

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imprimph profile image
Jaswanth

Hello Rahul, I am currently in my 3rd year of engineering, I like JavaScript a lot, so I started using it to solve algorithm and data structure questions in Leetcode and hackerrank.
My question is, can I use JavaScript in coding interviews?
Will companies provide, JavaScript as an option in their interviews?

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Rahul Author

Well, JavaScript is the only option for the companies brother. It actually depends on your role of what you're applying.

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Jaswanth

Yeah, I get your point. If I want to apply for Web developer roles or Front-end engineer or Back-end engineer, then JavaScript will definitely be an option. If I apply for an SDE role, then, will it be available?

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rahxuls profile image
Rahul Author

In interviews it's not like you are given options. When you'll apply they'll ask about your powerful skill and will ask question about it.

Can you tell me your tech stack? And more about you?

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imprimph profile image
Jaswanth

Ok, got it! Thanks :)

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rahxuls profile image
Rahul Author

Can you let me know more about you?

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imprimph profile image
Jaswanth

Yeah sure, currently I am pursuing 3rd year of my Computer Science degree, I am interested in web development and blockchain, so I started taking some udemy courses (Colt Steele's Web development boot camp and Jonas's Node course). Having completed these courses, I got familiar with javascript and web development. Now, I am focussing on DSA for coding interviews, by solving questions from Leetcode, Hackerrank.