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To loop through an array in JavaScript, you can use any of these methods –

1. Use sequential for loop – A for loop is used to execute a set of statements repeatedly until the condition becomes false.
2. Use for-of loop – A for-of loop makes it easier to iterate over arrays and other iterable objects.
3. Use do-while loop – A do…while loop is similar to a while loop, except that a do…while loop is guaranteed to execute at least one time.
4. Use while loop – A while loop repeats a set of statements until the condition becomes false.
5. Use Array.forEach() method – The forEach() method executes a provided function once per array element.

Let’s look at these methods in detail below.

Use Sequential for Loop To Loop Through An Array In JavaScript

A sequential for loop is the most basic type of loop. It has the following syntax −

for(initialization; condition; increment) {

// Statements inside the body of loop

}

The initialization statement initializes the loop; it’s executed once, when the loop starts. The condition statement evaluates the condition; if it’s true, the loop body is executed. If it’s false, the loop stops. The increment statement increments or decrements your loop counter.

The for loop has the following three parts −

Initialization − You initialize variables used in the loop (e.g., i = 0)

Condition − You define the condition for running the loop (e.g., i must be less than 5). If the condition evaluates to true, the loop body is executed. If the condition evaluates to false, the loop stops executing.

Increment/decrement − This statement increments or decrements your loop counter (e.g., i++) after each iteration through the loop.

Here’s an example of how to use a for loop to print all elements of an array –

var arr = [1,2,3,4,5];

for(i = 0; i < arr.length; i++) {

console.log(arr[i]);

}

Output

1

2

3

4

5

Use for-of Loop To Loop Through An Array In JavaScript

ES6 introduces the for-of loop, which makes it easier to iterate over arrays and other iterable objects –

var arr = ['a','b','c'];

for(var val of arr) {

console.log(val);

}

Output

a

b

c

Use do-while Loop To Loop Through An Array In JavaScript

A do-while loop is similar to a while loop, except that a do…while loop is guaranteed to execute at least one time.

The syntax of a do-while loop is as follows −

Syntax

do {

// Statements

} while(condition);

Here’s an example of how to use a do-while loop to print all elements of an array –

var arr = ['a','b','c'];

var i = 0;

do {

console.log(arr[i]);

i++;

} while (i<arr.length)

Output

a

b

c

Use while Loop To Loop Through An Array In JavaScript

A while loop is used to execute a set of statements repeatedly until the condition becomes false. The syntax of a while loop is as follows −

Syntax

while(condition) {

// Statements

}

Here’s an example of how to use a while loop to print all elements of an array –

var arr = ['a','b','c'];

var i = 0;

while(i < arr.length) {

console.log(arr[i]);

i++;

}

Output

a

b

c

Use Array.forEach() Method

The forEach() method executes a provided function once per array element.

The syntax of the forEach() method is as follows −

array.forEach(function(currentValue, index, arr), thisValue)

Here’s an example of how to use the forEach() method to print all elements of an array –

var arr = ['a','b','c'];

arr.forEach(function(element) {

console.log(element);

});

Output

a

b

c

Conclusion

In this article, we looked at how to loop through an array in JavaScript. We saw how to use for loop, for-of loop, while loop, do-while loop and forEach() method to loop through an array. Choose the method depending on your requirement.

I hope you found this article helpful. Thanks for reading!