switch Statement

The switch statement is used to perform different actions based on different conditions. It is an alternative to using multiple if...else if...else statements.

1. Basic switch Statement

Here is an example of a basic switch statement:

let day = 3;
let dayName;

switch (day) {
    case 0:
        dayName = "Sunday";
        break;
    case 1:
        dayName = "Monday";
        break;
    case 2:
        dayName = "Tuesday";
        break;
    case 3:
        dayName = "Wednesday";
        break;
    case 4:
        dayName = "Thursday";
        break;
    case 5:
        dayName = "Friday";
        break;
    case 6:
        dayName = "Saturday";
        break;
    default:
        dayName = "Invalid day";
}

console.log(dayName); // Outputs: Wednesday

2. switch with Multiple Cases

You can group multiple cases together if they should execute the same code:

let fruit = "apple";
let color;

switch (fruit) {
    case "apple":
    case "cherry":
        color = "red";
        break;
    case "banana":
        color = "yellow";
        break;
    case "grape":
        color = "purple";
        break;
    default:
        color = "unknown";
}

console.log(color); // Outputs: red

3. switch with Expressions

The switch statement can also use expressions in the cases:

let score = 85;
let grade;

switch (true) {
    case score >= 90:
        grade = "A";
        break;
    case score >= 80:
        grade = "B";
        break;
    case score >= 70:
        grade = "C";
        break;
    case score >= 60:
        grade = "D";
        break;
    default:
        grade = "F";
}

console.log(grade); // Outputs: B

4. switch without break

If the break statement is omitted, the next case will be executed regardless of the case value:

let number = 1;

switch (number) {
    case 1:
        console.log("One");
    case 2:
        console.log("Two");
    case 3:
        console.log("Three");
        break;
    default:
        console.log("Invalid number");
}

// Outputs:
// One
// Two
// Three