Loops in JavaScript

Baby Manisha Sunkara
3 min readJan 5, 2023

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Loops are an essential part of any programming language, and JavaScript is no exception. They allow you to repeat a block of code multiple times, which can be extremely useful for tasks such as iterating through an array or performing an operation on a large dataset.

In JavaScript, there are three main types of loops: for loops, while loops, and do-while loops.

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For Loops

A for loop is used to execute a block of code a specific number of times. It consists of three parts: an initialization expression, a condition, and an iteration expression.

Here is the basic syntax for a for loop:

for (initialization; condition; iteration) {
// code block to be executed
}

The initialization expression is executed before the loop begins. It is typically used to initialize a loop counter variable. The condition is checked before each iteration of the loop. If the condition is true, the code block within the loop is executed. If the condition is false, the loop is terminated. The iteration expression is executed at the end of each iteration and is typically used to update the loop counter.

Here is an example of a for loop that counts from 0 to 9:

for (let i = 0; i < 10; i++) {
console.log(i);
}

This for loop will print the numbers 0 through 9 to the console.

While Loops

A while loop is used to execute a block of code as long as a certain condition is true. The syntax for a while loop is as follows:

while (condition) {
// code block to be executed
}

The condition is checked before each iteration of the loop. If the condition is true, the code block within the loop is executed. If the condition is false, the loop is terminated.

Here is an example of a while loop that counts from 0 to 9:

let i = 0;
while (i < 10) {
console.log(i);
i++;
}

This while loop will print the numbers 0 through 9 to the console.

Do-While Loops

A do-while loop is similar to a while loop, except that the code block within the loop is guaranteed to execute at least once. The syntax for a do-while loop is as follows:

do {
// code block to be executed
} while (condition);

The code block within the loop is executed, and then the condition is checked. If the condition is true, the loop continues. If the condition is false, the loop is terminated.

Here is an example of a do-while loop that counts from 0 to 9:

let i = 0;
do {
console.log(i);
i++;
} while (i < 10);

This do-while loop will print the numbers 0 through 9 to the console.

Conclusion

Loops are an essential part of JavaScript and are useful for performing repetitive tasks. Whether you need to iterate through an array, perform an operation on a large dataset, or just repeat a task a certain number of times, loops are an invaluable tool. By understanding the different types of loops available in JavaScript, you can choose the one that is best suited to your needs.

Thanks

Baby Manisha Sunkara

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Baby Manisha Sunkara

I am a front-end developer located in AP, India. I have 9+ yrs of professional experience in developing small to large-scale websites and web-applications.