JavaScript Conditional Statement

Conditional statements in JavaScript are used to perform different actions based on different conditions. Here are the main types of conditional statements:

1. if Statement

Syntax

if(condition){
// code to be executed if condition is true
}

Example

let age = 20;

if (age >= 18) {
console.log(“You are an adult.”); // Output: You are an adult.
}

2. if…else Statement

Syntax

if (condition) {
// code to be executed if condition is true
} else {
// code to be executed if condition is false
}

Example

let age = 16;

if (age >= 18) {
console.log(“You are an adult.”);
} else {
console.log(“You are a minor.”); // Output: You are a minor.
}

3. if…else if…else Statement

Syntax

if (condition1) {
// code to be executed if condition1 is true
} else if (condition2) {
// code to be executed if condition2 is true
} else {
// code to be executed if all conditions are false
}

Example

let score = 85;

if (score >= 90) {
console.log(“Grade: A”);
} else if (score >= 80) {
console.log(“Grade: B”); // Output: Grade: B
} else if (score >= 70) {
console.log(“Grade: C”);
} else if (score >= 60) {
console.log(“Grade: D”);
} else {
console.log(“Grade: F”);
}

4. switch Statement

Syntax

switch (expression) {
case value1:
// code to be executed if expression === value1
break;
case value2:
// code to be executed if expression === value2
break;
// more cases…
default:
// code to be executed if no cases match
}

Example

let day = 3;
let dayName;

switch (day) {
case 1:
dayName = “Monday”;
break;
case 2:
dayName = “Tuesday”;
break;
case 3:
dayName = “Wednesday”; // Output: Wednesday
break;
case 4:
dayName = “Thursday”;
break;
case 5:
dayName = “Friday”;
break;
case 6:
dayName = “Saturday”;
break;
case 7:
dayName = “Sunday”;
break;
default:
dayName = “Invalid day”;
}

console.log(dayName);

5. Ternary Operator

Syntax

condition ? expressionIfTrue : expressionIfFalse;

Example

let age = 20;
let status = (age >= 18) ? “adult” : “minor”;
console.log(status); // Output: adult