JavaScript Loops - For, While, and Do-While

Loops are essential in JavaScript for repeating a block of code multiple times. In this guide, we'll explore three common types of loops: For, While, and Do-While loops, and provide examples to illustrate each type.

The For Loop

The for loop is often used when you know how many times you want to repeat a block of code:

for (let i = 0; i < 5; i++) {
    console.log(`Iteration ` + i);
}
    

The While Loop

The while loop continues to execute a block of code as long as a specified condition is true:

let count = 0;
while (count < 5) {
    console.log(`Count: ` + count);
    count++;
}
    

The Do-While Loop

The do-while loop is similar to the while loop, but it always executes the block of code at least once before checking the condition:

let num = 10;
do {
    console.log(`Number: ` + num);
    num--;
} while (num > 0);
    

Loop Control Statements

Loop control statements like break and continue allow you to modify the behavior of loops:

for (let i = 0; i < 5; i++) {
    if (i === 2) {
        continue; // Skip iteration when i is 2
    }
    console.log(`Iteration ` + i);
}
    

Nested Loops

You can use loops within loops to create complex patterns or iterate through multi-dimensional arrays:

for (let i = 1; i <= 3; i++) {
    for (let j = 1; j <= 3; j++) {
        console.log(i + ` x ` + j + ` = ` + (i * j));
    }
}
    

Conclusion

Loops are crucial for automating repetitive tasks in JavaScript. By understanding how to use for, while, and do-while loops, as well as loop control statements, you can efficiently handle various programming challenges.

Happy coding!