break and continue

When you write loops, you sometimes need more control over how they run. Instead of letting a loop finish every single iteration, you might want to stop it early when you find what you’re looking for, or skip an iteration if it doesn’t match your criteria. JavaScript provides two statements for this: break and continue.

Exiting entirely: the break statement

The break statement terminates the current loop completely. When JavaScript encounters break, it immediately stops running the loop and moves on to the code that comes after the loop.

This is extremely useful when searching for something. Once you find it, there is no need to keep checking the rest of the items!

let count = 0;
for (let i = 1; i <= 5; i++) {
  if (i === 3) {
    break; // Stop the loop entirely when i is 3
  }
  count++;
}
// Control jumps here after the break
console.log("Final count:", count);

Skipping an iteration: the continue statement

The continue statement is different. It doesn’t destroy the loop; it just terminates the current iteration. When JavaScript sees continue, it skips the rest of the loop body for that iteration and jumps straight to the next iteration.

let count = 0;
for (let i = 1; i <= 5; i++) {
  if (i === 3) {
    continue; // Skip the rest of this iteration
  }
  count++;
}
console.log("Final count:", count);

[!TIP] In a for loop, using continue still evaluates the update expression (like i++). The loop counter progresses as normal!

Let’s test your understanding of this. What do you think the following code will print?

for (let i = 0; i < 5; i++) {
  if (i === 2) {
    continue;
  }
  console.log(i);
}

0
1
3
4

The while loop trap

There is a major gotcha when using continue inside a while loop. Because while loops don’t have a built-in update expression like for loops, you usually manually update your counter inside the loop body.

If you use continue before updating your counter, you will create an infinite loop!

let i = 0;
let iters = 0;
try {
  while (i < 3) {
    if (i === 1) {
      if (iters++ > 10) throw new Error('Infinite loop detected!');
      // DANGER: We forgot to increment 'i' before continuing!
      continue; 
    }
    i++;
  }
} catch (e) {
  console.log(e.message);
}

Infinite loop detected!

To fix this, you must ensure that your loop condition variable is updated before the continue statement is executed.

Labels and Nested Loops

By default, break and continue only affect the innermost loop they are inside. If you have a loop inside another loop (nested loops), a break in the inner loop will not stop the outer loop.

let loopBreaks = 0;
for (let i = 0; i < 3; i++) {
  switch (i) {
    case 1:
      // This break ONLY exits the switch, not the for loop!
      break; 
  }
  loopBreaks++;
}
console.log("The loop ran", loopBreaks, "times.");

The loop ran 3 times.

If you really need to break out of an outer loop from an inner loop, you can use a label. A label is an identifier followed by a colon (:) placed before a loop. You can then reference this label in your break or continue statement.

let found = false;

outerLoop: for (let i = 0; i < 3; i++) {
  for (let j = 0; j < 3; j++) {
    if (i === 1 && j === 1) {
      found = true;
      break outerLoop; // Escapes BOTH loops!
    }
  }
}

console.log("Found:", found);

Found: true

Using labels is rare, but they are a powerful tool when you are deeply nested and need an immediate escape hatch.

Practice