Break statement in Javascript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the break statement do in JavaScript loops?

The break statement immediately stops the loop and exits it, skipping any remaining iterations.

beginner

Can break be used outside of loops in JavaScript?

No, break is used only inside loops (for, while, do-while) or switch statements to exit them early.

intermediate

What happens if you use break inside a nested loop?

The break statement only exits the innermost loop where it is used, not all outer loops.

beginner

Example: What will this code output?<br><pre>for(let i = 0; i < 5; i++) {<br>  if(i === 3) break;<br>  console.log(i);<br>}</pre>

It will print:
0
1
2
Because when i becomes 3, the break stops the loop immediately.

beginner

How does break differ from continue in loops?

break stops the entire loop immediately.
continue skips only the current iteration and moves to the next one.

What does the break statement do inside a loop?

A Skips the current iteration and continues

B Stops the loop immediately and exits it

C Restarts the loop from the beginning

D Does nothing special

break immediately stops the loop and exits it.

Where can you use the break statement in JavaScript?

A Only inside functions

B Anywhere in the code

C Inside loops and switch statements

D Only inside if statements

break is valid inside loops and switch statements.

What happens if break is used inside nested loops?

A It causes an error

B It exits all loops

C It skips the current iteration

D It exits only the innermost loop

break exits only the loop where it is used, usually the innermost one.

What will this code print?

for(let i=0; i<3; i++) { if(i===1) break; console.log(i); }

A 0

B 0 1

C 1 2

D 0 1 2

When i is 1, break stops the loop, so only 0 is printed.

How is break different from continue?

A <code>break</code> stops the loop; <code>continue</code> skips current iteration

B <code>break</code> skips current iteration; <code>continue</code> stops the loop

C Both do the same thing

D Neither affects the loop

break stops the loop; continue skips only the current iteration.

Explain how the break statement works inside a loop and give a simple example.

Think about when you want to stop repeating something early.

Describe the difference between break and continue in loops.

One stops all, the other skips one.

Practice

1. What does the break statement do inside a loop in JavaScript?

easy

A. Pauses the loop for a moment

B. Stops the loop immediately and exits it

C. Restarts the loop from the beginning

D. Skips the current iteration and continues with the next

Solution

1. Step 1: Understand the purpose of break

   The break statement is used to stop a loop or switch case immediately.

2. Step 2: Compare with other loop controls

   Unlike continue which skips to the next iteration, break exits the loop fully.

3. Final Answer:

   Stops the loop immediately and exits it -> Option B

4. Quick Check:

   break stops loop = D [OK]

Hint: Break exits loop immediately, unlike continue which skips iteration [OK]

Common Mistakes:

• Confusing break with continue
• Thinking break pauses the loop
• Assuming break restarts the loop

2. Which of the following is the correct syntax to use break inside a for loop?

easy

A. for(let i=0; i<5; i++) { if(i===3) break; }

B. for(let i=0; i<5; i++) { break if(i===3); }

C. for(let i=0; i<5; i++) { if break(i===3); }

D. for(let i=0; i<5; i++) { if(i===3) continue break; }

Solution

1. Step 1: Check the correct placement of break

   The break statement must be inside a block and triggered by a condition like if(i===3).

2. Step 2: Validate syntax correctness

   for(let i=0; i<5; i++) { if(i===3) break; } uses correct JavaScript syntax: if(condition) break;. Other options misuse break syntax.

3. Final Answer:

   for(let i=0; i<5; i++) { if(i===3) break; } -> Option A

4. Quick Check:

   Correct break syntax = B [OK]

Hint: Use break inside if block: if(condition) break; [OK]

Common Mistakes:

• Placing break before if
• Using break as a function
• Combining continue and break incorrectly

3. What will be the output of this code?

let sum = 0;
for(let i = 1; i <= 5; i++) {
  if(i === 3) break;
  sum += i;
}
console.log(sum);

medium

A. 3

B. 6

C. 10

D. 15

Solution

1. Step 1: Trace the loop iterations

   The loop runs from i=1 to i=5, but breaks when i equals 3, so it runs for i=1 and i=2 only.

2. Step 2: Calculate the sum before break

   sum = 0 + 1 + 2 = 3; loop breaks before adding 3.

3. Final Answer:

   3 -> Option A

4. Quick Check:

   Sum before break at i=3 = 3 [OK]

Hint: Add only before break triggers; break stops loop early [OK]

Common Mistakes:

• Adding value after break condition
• Assuming loop runs fully
• Confusing break with continue

4. Find the error in this code snippet:

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

medium

A. Missing semicolon after break causes syntax error

B. break cannot be used inside for loops

C. No error, code runs correctly

D. console.log should be before break

Solution

1. Step 1: Check syntax of break statement

   In JavaScript, semicolon after break is optional if line ends there, so no syntax error.

2. Step 2: Verify loop and break usage

   break is valid inside for loops and console.log after break is fine; code stops when i=2.

3. Final Answer:

   No error, code runs correctly -> Option C

4. Quick Check:

   break syntax valid without semicolon = C [OK]

Hint: Semicolon after break is optional if line ends there [OK]

Common Mistakes:

• Thinking semicolon is mandatory after break
• Believing break can't be in loops
• Assuming console.log must be before break

5. You want to find the first number divisible by 7 in an array and stop checking after finding it. Which code correctly uses break to do this?

const numbers = [10, 13, 21, 28, 35];
let result = null;
for(let num of numbers) {
  if( /* condition here */ ) {
    result = num;
    break;
  }
}
console.log(result);

hard

A. if(num === 7)

B. if(num / 7 === 0)

C. if(num % 7)

D. if(num % 7 === 0)

Solution

1. Step 1: Identify condition for divisibility by 7

   Use modulo operator: num % 7 === 0 checks if remainder is zero, meaning divisible.

2. Step 2: Confirm break usage stops loop after first match

   When condition is true, assign result and break to stop checking further.

3. Final Answer:

   if(num % 7 === 0) -> Option D

4. Quick Check:

   Modulo zero means divisible = A [OK]

Hint: Use modulo (%) to check divisibility, then break [OK]

Common Mistakes:

• Using division instead of modulo
• Checking if num equals 7 only
• Using if(num % 7) which is truthy for non-zero