Javascript Switch

JavaScript switch Statement 🔄

The switch statement is used for multiple conditional checks, making the code cleaner than multiple if...else if...else statements.

1️⃣ Basic Syntax

switch (expression) {
    case value1:
        // Code to execute if expression === value1
        break;
    case value2:
        // Code to execute if expression === value2
        break;
    default:
        // Code to execute if none of the cases match
}

• expression is compared (===) with each case.
• break prevents execution from falling to the next case.
• default runs if no match is found.

2️⃣ Example: Simple switch

let fruit = "apple";

switch (fruit) {
    case "banana":
        console.log("Bananas are yellow.");
        break;
    case "apple":
        console.log("Apples are red.");
        break;
    case "grape":
        console.log("Grapes are purple.");
        break;
    default:
        console.log("Unknown fruit.");
}

📌 Output: "Apples are red."

3️⃣ default Case

Runs when no cases match.

let color = "blue";

switch (color) {
    case "red":
        console.log("Red like fire.");
        break;
    case "green":
        console.log("Green like grass.");
        break;
    default:
        console.log("Color not recognized.");
}

📌 Output: "Color not recognized."

4️⃣ Multiple Cases, Same Output

Cases can share the same code.

let day = "Saturday";

switch (day) {
    case "Saturday":
    case "Sunday":
        console.log("It's the weekend!");
        break;
    case "Monday":
    case "Tuesday":
    case "Wednesday":
    case "Thursday":
    case "Friday":
        console.log("It's a weekday.");
        break;
    default:
        console.log("Invalid day.");
}

📌 Output: "It's the weekend!" (if day = "Saturday")

5️⃣ switch Without break (Fall-through)

If break is omitted, execution continues to the next case.

let grade = "B";

switch (grade) {
    case "A":
        console.log("Excellent!");
    case "B":
        console.log("Good job!");
    case "C":
        console.log("You passed.");
        break;
    default:
        console.log("Try again.");
}

📌 Output:

Good job!
You passed.

🚨 Warning: Use break to avoid unintended behavior.

6️⃣ switch with Expressions

You can use mathematical expressions.

let num = 10;

switch (true) {
    case num < 10:
        console.log("Number is less than 10.");
        break;
    case num === 10:
        console.log("Number is exactly 10.");
        break;
    case num > 10:
        console.log("Number is greater than 10.");
        break;
}

📌 Output: "Number is exactly 10."

🎯 Summary

✅ switch is useful for multiple conditions
✅ break prevents fall-through
✅ default handles unmatched cases
✅ Multiple cases can share code
✅ switch (true) can handle range conditions

🚀 Now you can use switch efficiently! Let me know if you have any questions. 😊