JavaScript Switch

What is Switch Case in JavaScript?

In JavaScript, a switch case is a conditional statement that is used so it can provide a way to execute the statements based on their conditions or different conditions. A switch case statement is used to perform different actions based on the conditions that are present in the program or given by the user. In other words, a switch statement evaluates the condition to match the condition with the series of cases and if the condition is matched then it executes the statement. If the condition is not matched with any case then the default condition will be executed. In JavaScript, a switch case statement is an alternative approach for if else conditions. The JavaScript switch statement is used to execute one code from multiple expressions. But it is convenient that if else if because it can be used with numbers, characters etc.

Key Points on Switch Statement:

• The switch statement evaluates an expression and compares its value against different case labels.
• Each case ends with a break statement to stop further execution after a match.
• The default case is optional and runs if none of the cases match the expression.
• The switch statement is typically used when multiple conditions need to be checked based on a fixed set of values.
• If no break is used, the execution will "fall through" and execute the code in the following case, which might not be the intended behavior.

Syntax of Switch Statement:

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

Example of Switch Statement in JavaScript:

This example uses a switch statement to check the day of the week based on a number.

let day = 3;
switch (day) {
    case 1:
        console.log("Monday");
        break;
    case 2:
        console.log("Tuesday");
        break;
    case 3:
        console.log("Wednesday");
        break;
    case 4:
        console.log("Thursday");
        break;
    case 5:
        console.log("Friday");
        break;
    case 6:
        console.log("Saturday");
        break;
    case 7:
        console.log("Sunday");
        break;
    default:
        console.log("Invalid day");
    }

Detailed Explanation:

• Expression: The variable or expression in the switch statement is evaluated once.
• Case Labels: The result of the expression is compared against each case, and the corresponding code block is executed when a match is found.
• Break Statement: After the code in a matched case executes, the break statement terminates the switch statement.
• Default Case: The optional default case executes if no match is found for the expression. This is useful for handling unexpected values.
• Efficiency: Switch is generally more efficient than a series of if-else statements when there are multiple possible conditions to check.
• Limitations: JavaScript's switch statement can only compare values using strict equality (===). It does not support other types of comparisons or ranges.

By using switch statements effectively, developers can create cleaner and more readable code when dealing with multiple conditions that are based on fixed values.