JavaScript Loops: why we use them - the first 3 types

while learning javascript I came across loops

but before learning different types of loops, I want understand one question - why do we use loops?

Why do we use loops?

Loops allow us to repeat a block of code without rewrite same code again and again.

For example , without loop:

 console.log(1);
 console.log(2);
 console.log(3);
 console.log(4);
 console.log(5);

with loop:

for(let i=1;i<=5;i++){
       console.log(i);
}

The loop becomes especially useful when working with large amounts of data, such as arrays.

Types of loop:

1.for loop:
A for loop is useful when you know how many times you want to repeat something.

for (let i = 1; i <= 5; i++) {
   console.log(i); 
}

2.while loop:

A while loop checks the condition before executing the code.

let i = 1;

while (i <= 5) {
    console.log(i);
    i++;
}

If the condition is false from the beginning, the loop won't execute.

3. do...while Loop

A do...while loop executes the code first and checks the condition afterward.

let i = 1;

do {
    console.log(i);
    i++;
} while (i <= 5);

This means it will execute at least once.

Quick way to remember

for - repeat with initialization, condition & update
while - check → execute
do...while - execute → check

The key difference:

while can execute zero times, but do...while executes at least once.