In JavaScript, both forEach and for loops are used to iterate over arrays or collections, but they differ in usage and behavior. forEach is a higher-order function that simplifies iteration with built-in array methods, while for loops offer more control, flexibility, and broader application.

For Loop

The for loop is one of the original ways to iterate through arrays or collections in JavaScript. It allows you to specify the initialization, condition, and increment all in one line, making it ideal when the iteration count is known.

Syntax

for (initialization; condition; increment)  
{  
   // code to be executed
}

Example: In this example, this loop iterates from 1 to 5. For each iteration, it logs the current value of i to the console.

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

1
2
3
4
5

forEach loop

The forEach() method is also used to loop through arrays, but it uses a function differently than the classic “for loop”. It passes a callback function for each element of an array together with the below parameters:

• Current Value (required): The value of the current array element
• Index (optional): The index number of the current element
• Array (optional): The array object the current element belongs to

We need a callback function to loop through an array by using the forEach method.

Syntax

numbers = [1, 2, 3, 4, 5];
numbers.forEach(function(number) {
   // code to be executed
});

For every single element of the array, the function will be executed. The callback should have at least one parameter which represents the elements of an array.

Example: This example shows the use of the index parameter in the forEach method.

numbers = [1, 2, 3, 4, 5];

numbers.forEach((number, index) => {
    console.log('Index: ' + index +
        ', Value: ' + number);
});

Index: 0, Value: 1
Index: 1, Value: 2
Index: 2, Value: 3
Index: 3, Value: 4
Index: 4, Value: 5

Difference between For loop and for each loop

Conclusion

The for loop is better suited when performance, control over iterations, or early exit conditions are important. The forEach loop, on the other hand, is ideal for clean, readable code when looping through arrays without needing complex logic. Choosing between the two depends on the specific requirements of your code.