JavaScript While Loop
The while loop executes a block of code as long as a specified condition is true. In JavaScript, this loop evaluates the condition before each iteration and continues running as long as the condition remains true. The loop terminates when the condition becomes false, enabling dynamic and repeated operations based on changing conditions.
Syntax
while (condition) {
Code block to be executed
}
Example: Here’s an example of a while loop that counts from 1 to 5.
let count = 1;
while (count <= 5) {
console.log(count);
count++;
}
Output
1 2 3 4 5
Do-While loop
A Do-While loop is another type of loop in JavaScript that is similar to the while loop, but with one key difference: the do-while loop guarantees that the block of code inside the loop will be executed at least once, regardless of whether the condition is initially true or false.
Syntax
do {
// code block to be executed
} while (condition);
Example : Here’s an example of a do-while loop that counts from 1 to 5.
let count = 1;
do {
console.log(count);
count++;
} while (count <= 5);
Output
1 2 3 4 5
Comparison between the while and do-while loop:
The do-while loop executes the content of the loop once before checking the condition of the while loop. While the while loop will check the condition first before executing the content.
While Loop | Do-While Loop |
|---|---|
It is an entry condition looping structure. | It is an exit condition looping structure. |
The number of iterations depends on the condition mentioned in the while block. | Irrespective of the condition mentioned in the do-while block, there will a minimum of 1 iteration. |
The block control condition is available at the starting point of the loop. | The block control condition is available at the endpoint of the loop. |