Conditional Statement in Js

What is conditional statement?

Conditional Statement is used to make decisions in a program based on a condition.

Type:

• if
• if else
• else if
• nested if
• switch

if Statement

The if statement is used to execute a block of code only when a condition is true.

let age = 20;

if (age >= 18) {
    console.log("Eligible to vote");
}

if else Statement

The if...else statement is used to execute one block of code if the condition is true, and another block if the condition is false.

let age = 16;

if (age >= 18) {
    console.log("Eligible to vote");
} else {
    console.log("Not eligible to vote");
}

else if Statement

The else if statement is used to check multiple conditions and execute the block of the first true condition.

let marks = 85;

if (marks >= 90) {
    console.log("Grade A+");
} else if (marks >= 75) {
    console.log("Grade A");
} else if (marks >= 50) {
    console.log("Pass");
} else {
    console.log("Fail");
}

Nested if Statement

A nested if is an if statement placed inside another if statement. It is used to check multiple dependent conditions.

let age = 20;
let hasID = true;

if (age >= 18) {
    if (hasID) {
        console.log("Eligible to vote");
    } else {
        console.log("ID is required");
    }
} else {
    console.log("Not eligible");
}

switch Statement

The switch statement is used to select one block of code from multiple options based on the value of an expression.

let day = 2;

switch (day) {
    case 1:
        console.log("Monday");
        break;
    case 2:
        console.log("Tuesday");
        break;
    case 3:
        console.log("Wednesday");
        break;
    default:
        console.log("Invalid Day");
}