JavaScript Break and Continue

In JavaScript, break and continue are used to control loop execution. break immediately terminates a loop when a condition is met, while continue Skips the current iteration and proceeds to the next loop iteration. Additionally, JavaScript supports labels, which can be used with break and continue to control nested loops efficiently.

The break Statement

The break statement is used to exit a loop when a certain condition is satisfied. It is commonly used when searching for a specific value in an array or when an early exit from a loop is required.

Syntax

break;

Using break in a for loop

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Breaking the loop at 5

In this example

• The loop starts from i = 0 and iterates up to i < 10.
• When i reaches 5, the break statement executes, terminating the loop immediately.
• Numbers 0 to 4 are printed before the loop stops.

Using break in a while Loop

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Loop stopped at 6

In this example

• The loop starts from n = 1 and runs as long as n <= 10.
• When n reaches 6, the break statement is executed, stopping the loop.
• The numbers 1 to 5 are printed before the loop terminates.

The Continue statement

The continue statement skips the current iteration of the loop and moves to the next iteration without terminating the loop.

Syntax

continue;

Using continue in a for Loop

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In this example

• The loop iterates from i = 0 to i < 10.
• If i is an even number (i % 2 === 0), the continue statement is executed, skipping that iteration.
• Only odd numbers are printed.

Using continue in a while Loop

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In this example

• The loop starts from i = 0 and runs while i < 10.
• If i is a multiple of 3, the continue statement skips that iteration.
• Numbers 3, 6, and 9 are not printed.

JavaScript Labels

Labels in JavaScript provide a way to name a loop, which can then be referenced using break or continue. This is useful when dealing with nested loops, where break or continue needs to be applied to a specific loop.

Syntax

labelName:
 statement;

Using break with Labels

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In this example

• The outerLoop label marks the outer for loop.
• When j === 1, the break outerLoop; statement terminates both inner and outer loops.

Using continue with Labels

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In this example

• When j === 1, the continue outerLoop; statement skips to the next iteration of the outer loop.
• The inner loop execution stops early, printing only j = 0 for each i.

Conclusion

The break, continue, and label statements are powerful tools for controlling loop execution in JavaScript.

• Use break when you need to exit a loop entirely.
• Use continue when you want to skip specific iterations but continue looping.
• Use labels to control nested loops effectively.