Iteration is the repetition of a process in order to generate an outcome. In JavaScript, you can iterate an array using for-loop, while-loop, foreach, every method, map, etc.
- for loop
- while loop
- forEach method
- every method
- Using map
Examples of JavaScript iterate array
Let’s see HTML examples code:-
1. for loop
The for loop is used to iterate over a sequence. Let’s print all values of the array in the console.
<!DOCTYPE html>
<html>
<head>
<script>
arr1 = [ 1, 2, 3, 4, 5 ];
for (index = 0; index < arr1.length; index++) {
console.log(arr1[index]);
}
</script>
</head>
<body>
</body>
</html>Output:
2. while loop
The while loop loops through a block of code as long as a specified condition is true.
<script>
arr1 = [ 1, 2, 3, 4, 5 ];
while (index < arr1.length) {
console.log(arr1[index]);
index++;
}
</script> 3. forEach method
The forEach() method calls a function once for each element in an array, in order.
<script>
arr1 = [ 1, 2, 3, 4, 5 ];
arr1.forEach(myFunction);
function myFunction(item, index)
{
console.log(item);
}
</script>4. every method
Every method executes the provided callback function once for each element present in the array until it finds the one where callback returns a falsy value.
<script>
arr1 = [ 1, 2, 3, 4, 5 ];
const under_five = x => x < 5;
if (arr1.every(under_five)) {
console.log('All are less than 5');
}
else {
console.log('At least one element is not less than 5');
}
</script> Output: At least one element is not less than 5
5. Using map
The Map object holds key-value pairs and remembers the original insertion order of the keys.
<!DOCTYPE html>
<html>
<head>
<script>
arr1 = [ 1, 2, 3, 4, 5 ];
square = x => Math.pow(x, 2);
squares = array.map(square);
console.log(array);
console.log(squares);
</script>
</head>
<body>
</body>
</html>Output:
Note: In the first example only we used complete HTML code and output screenshot. You can do the same coding with others.
Do comment if you have another way to do it or have any doubts on this topic.
Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.
OS: Windows 10
Code: HTML 5 Version