Labeled break and continue in Javascript - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of nested loops with labeled break

What is the output of this JavaScript code using a labeled break?

Javascript

outerLoop: for (let i = 1; i <= 3; i++) {
  for (let j = 1; j <= 3; j++) {
    if (i * j > 3) {
      break outerLoop;
    }
    console.log(`${i},${j}`);
  }
}

A "1,1\n1,2\n2,1\n2,2\n3,1"

B "1,1\n1,2\n2,1"

C "1,1\n1,2\n2,1\n2,2"

D "1,1\n1,2\n1,3\n2,1\n2,2"

💡 Hint

Remember that labeled break exits the entire outer loop immediately.

The code prints pairs until i*j > 3. When i=2 and j=3, 2*3=6 > 3, so break outerLoop stops all loops. The last printed pair is 2,2.

❓ Predict Output

intermediate

Output of nested loops with labeled continue

What is the output of this JavaScript code using a labeled continue?

Javascript

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

A "1,1\n2,1\n3,1"

B "1,1\n1,3\n2,1\n2,3\n3,1\n3,3"

C "1,1\n1,3\n2,1\n3,1"

D "1,1\n2,1\n3,1\n3,3"

💡 Hint

Labeled continue skips to the next iteration of the outer loop.

When j equals 2, continue outer skips the rest of the inner loop and goes to the next i. So only j=1 is printed for each i.

🔧 Debug

advanced

Identify the error with labeled continue usage

What error does this JavaScript code produce?

Javascript

outer: for (let i = 0; i < 2; i++) {
  for (let j = 0; j < 2; j++) {
    if (j === 1) {
      continue inner;
    }
    console.log(i, j);
  }
}

A SyntaxError: Unexpected identifier

B ReferenceError: inner is not defined

C No error, outputs: 0 0 1 0

D TypeError: continue label must be an identifier

💡 Hint

Check if the label used in continue exists.

The label 'inner' is not defined anywhere, so using 'continue inner;' causes a ReferenceError.

❓ Predict Output

advanced

Output with nested labeled break and continue

What is the output of this JavaScript code?

Javascript

outer: for (let i = 1; i <= 3; i++) {
  inner: for (let j = 1; j <= 3; j++) {
    if (i === j) {
      continue outer;
    }
    if (i + j === 4) {
      break inner;
    }
    console.log(`${i},${j}`);
  }
}

A "1,2\n2,1\n3,1\n3,2"

B "1,2\n1,3\n2,1\n3,1\n3,2"

C "1,2\n2,1\n3,1"

D "1,2\n2,1\n3,2"

💡 Hint

Remember continue outer skips to next i, break inner exits inner loop.

When i===j, continue outer skips to next i. When i+j===4, break inner exits inner loop. The printed pairs are 1,2 then next i=2, j=1 then i=3, j=1 and j=2.

🧠 Conceptual

expert

Effect of labeled break on loop execution

Consider this code snippet:

label1: for (let a = 0; a < 2; a++) {
  label2: for (let b = 0; b < 2; b++) {
    if (a === b) {
      break label1;
    }
    console.log(a, b);
  }
}

What is the value of variable a after the loops finish?

A 1

B undefined

C 2

D 0

💡 Hint

Labeled break exits the outer loop immediately when condition is met.

The break label1 stops the outer loop when a === b (which is true at a=0,b=0). The outer loop ends immediately, so a remains 0 after the loops finish.