How do I use iterators in JavaScript?

How do I use iterators in JavaScript?

In JavaScript, iterators are objects that allow you to traverse through a collection, like arrays or strings. You can create your own iterator by implementing the next() method.

Can you show me an example of a custom iterator?

Sure! Here's a simple example:

function createIterator(array) {
    let index = 0;
    return {
        next: function() {
            if (index < array.length) {
                return { value: array[index++], done: false };
            } else {
                return { done: true };
            }
        }
    };
}

const myArray = [1, 2, 3];
const iterator = createIterator(myArray);
console.log(iterator.next()); // { value: 1, done: false }
console.log(iterator.next()); // { value: 2, done: false }
console.log(iterator.next()); // { value: 3, done: false }
console.log(iterator.next()); // { done: true }

What are the benefits of using iterators?

Iterators provide a consistent way to access elements in a collection without exposing the underlying structure. They also allow for lazy evaluation, which can improve performance.

Are there built-in iterators in JavaScript?

Yes, JavaScript has built-in iterators for many data structures, such as arrays, strings, and maps. You can use methods like forEach, map, and filter that utilize these iterators.