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The break and continue statements in JavaScript

Break and continue statements

The break statement is used to exit a loop completely once a condition has been met, or
after x number of iterations. As such it is commonly used within an if conditional block.
Take as an example the following code:

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

This will print out the value of variable i from 0 to 5. However, what if we only want to print out till the number 3 and then exit from the loop?

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

With the break statement now included, the loop executes in the following manner:

  1. The for-loop starts execution
  2. The if conditional block checks for when i will be strictly equal to the number 3
  3. When it is, then the break statement ensures an exit from the loop completely
  4. As such, only numbers from 0 to 2 are logged as the loop only executes till i is 0, 1 and 2.

See the following output to the console:

0
1
2

The continue statement will terminate the current instance of an iteration in a loop. This is better explained with an example, wherein all the numbers from 0 to 5 are logged with
except the number 3.

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

The continue keyword changes the iteration in the following manner:

  1. The if conditional block checks if the value of i at the current iteration is 3.
  2.  If so, the instance of that current iteration in the loop exits by using the continue keyword.
  3.   The rest of the loop executes as is expected starting from the next iteration, with i starting at 4.

The result will be:

1
2
4
5

 

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