Stage-14

Loops in JavaScript

Loops are used in JavaScript to perform repeated tasks based on a condition. Conditions typically return true or false. A loop will continue running until the defined condition returns false.

Practice File : loops.js

Types of Loops

1. for Loop

The for loop is the most commonly used loop. It has three parts: initialization, condition, and increment/decrement.

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

2. while Loop

The while loop runs as long as the specified condition is true.

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

3. do...while Loop

The do...while loop is similar to the while loop, but it will always execute the block of code once before checking the condition.

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

4. for...in Loop

The for...in loop is used to iterate over the properties of an object.

const obj = {a: 1, b: 2, c: 3};
for (let key in obj) {
    console.log(key + ': ' + obj[key]);
}

5. for...of Loop

The for...of loop is used to iterate over iterable objects like arrays, strings, etc.

const arr = [1, 2, 3, 4, 5];
for (let value of arr) {
    console.log(value);
}

Example: