Arrays are sometimes referred to as List-like objects.

forEach vs. for Loops

forEach is an array method, just like push() or pop(), that is simply a loop that accesses each item in an array.

Example

const fruits = ['apple', 'pear', 'cherry'];
let capitalizedFruits = [];

fruits.forEach( fruit => {
   let capitalizedFruit = fruit.toUpperCase();
   capitalizedFruits.push(capitalizedFruit);
});

console.log(capitalizedFruits); // output: 'APPLE', 'PEAR', 'CHERRY'

forEach() is better than a for loop in every way.
Except for one con; you can’t break out of the iteration early before the end of the array. If you come across this case, use for or while instead.

forEach() Parameters

As you can see from the example above, forEach() takes a callback function as an argument with the an array item variable as its parameter.

array.forEach(currentItem => {...});

But the callback also takes more parameters, such as the index of the current array item, and the whole array itself.

array.forEach( function callback(currentItem, index, array) {
   ...
});

Example

const fruits = ['apple', 'pear', 'cherry'];
let capitalizedFruits = [];

fruits.forEach( (fruit, index) => {
   let capitalizedFruit = fruit.toUpperCase();
   capitalizedFruits.push(capitalizedFruit);
   console.log(`${index + 1}. ${fruit}`);
});

/* output: 
1. APPLE
2. PEAR
3. CHERRY
*/