Loops are an essential part of programming, allowing us to repeat a block of code multiple times until a certain condition is met. When working with arrays or other data structures, we often need to iterate through each element more than once. That’s where nested loops come into play. This guide will help you understand what nested loops are, when to use them, and how to implement them correctly in your JavaScript projects.
What Are Nested Loops?
A loop inside another loop is called a nested loop. The outer loop controls the number of times the inner loop runs. Let’s take a look at this example using two for loops:
for (let i = 0; i < 3; i++) {
console.log("Outer loop iteration:", i);
for (let j = 0; j < 2; j++) {
console.log("\tInner loop iteration:", j);
}
}The output would be:
Outer loop iteration: 0
Inner loop iteration: 0
Inner loop iteration: 1
Outer loop iteration: 1
Inner loop iteration: 0
Inner loop iteration: 1
Outer loop iteration: 2
Inner loop iteration: 0
Inner loop iteration: 1