What Are JavaScript Loops? See Examples in detail

Loops are used in JavaScript to repeat a block of code multiple times until a certain condition is met. They help reduce redundancy and make your code more efficient.

This blog explains the different types of loops with examples.


1. Why Use Loops?

Without loops, you would have to write repetitive code:

console.log("Hello");
console.log("Hello");
console.log("Hello");

With loops, the same task can be done in fewer lines:

for(let i = 0; i < 3; i++){
  console.log("Hello");
}

2. The for Loop

The for loop is commonly used when you know how many times you want to repeat the code.

Syntax:

for(initialization; condition; increment/decrement){
   // code to run
}

Example:

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

3. The while Loop

The while loop repeats as long as the condition is true. Use it when you don’t know how many iterations will be needed.

Syntax:

while(condition){
   // code to run
}

Example:

let i = 1;
while(i <= 5){
  console.log("Number " + i);
  i++;
}

4. The do-while Loop

The do-while loop runs at least once and then checks the condition.

Syntax:

do {
   // code to run
} while(condition);

Example:

let i = 1;
do {
  console.log("Number " + i);
  i++;
} while(i <= 5);

5. Loop Control Statements

break

Stops the loop immediately.

for(let i = 1; i <= 5; i++){
  if(i === 3) break;
  console.log(i);
}
// Output: 1, 2

continue

Skips the current iteration and continues with the next.

for(let i = 1; i <= 5; i++){
  if(i === 3) continue;
  console.log(i);
}
// Output: 1, 2, 4, 5

6. Nested Loops

Loops can be placed inside other loops.

Example:

for(let i = 1; i <= 3; i++){
  for(let j = 1; j <= 2; j++){
    console.log(`i=${i}, j=${j}`);
  }
}

7. Looping Through Arrays

for loop

let fruits = ["Apple", "Banana", "Mango"];
for(let i = 0; i < fruits.length; i++){
  console.log(fruits[i]);
}

for…of loop (ES6)

for(let fruit of fruits){
  console.log(fruit);
}

forEach method

fruits.forEach(fruit => console.log(fruit));

Conclusion

Loops are essential in JavaScript for reducing repetitive code and handling tasks dynamically. Understanding different types of loops and their control statements helps in building efficient programs.


📌 Citations

🔗 View other articles about Javascript:
https://savanka.com/category/learn/js/

🔗 External Javascript Documentation:
https://www.w3schools.com/js/

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