JavaScript Break Statement

The `break` statement in JavaScript is used to exit from a loop or a `switch` statement. It can be used to terminate the loop execution immediately or to break out of a `switch` statement.

1. Breaking Out of Loops

The `break` statement is commonly used to exit loops early when a specific condition is met. It can be used with `for`, `while`, and `do-while` loops:

// Using break in a for loop
for (let i = 0; i < 10; i++) {
    if (i === 5) {
        break; // Exit the loop when i equals 5
    }
    console.log(i);
}
// Output: 0 1 2 3 4

            

In this example, the `break` statement terminates the loop when `i` equals 5, so the loop only executes until 4.

2. Breaking Out of Switch Statements

In a `switch` statement, the `break` statement is used to prevent the execution from falling through to subsequent `case` blocks:

// Using break in a switch statement
let day = 3;
let dayName;

switch (day) {
    case 1:
        dayName = "Monday";
        break;
    case 2:
        dayName = "Tuesday";
        break;
    case 3:
        dayName = "Wednesday";
        break;
    default:
        dayName = "Invalid day";
}

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

            

Here, the `break` statement prevents the execution from continuing into the `default` case after the `case 3` block executes.