Nested Loop

A nested loop is simply a loop inside another loop. The inner loop will complete all its iterations for each single iteration of the outer loop.

A good analogy for this is a clock: for each hour (outer loop), the minute hand (inner loop) must complete its full 60-minute cycle.

Example of a nested loop:

let rows = 2;
let cols = 2;
for (let x = 0; x < rows; x++) {
	for (let y = 0; y < cols; y++) {
		console.log(x, y);
	}
}

// This will output:
// 0 0
// 0 1
// 1 0
// 1 1

The outer loop (x) runs rows times, and for each of those times, the inner loop (y) runs cols times. Each loop has its own counter: y starts again from 0 every time the outer loop runs, while rows and cols stay the same and only tell the loops when to stop.