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

What are some built-in iterators in JavaScript?

JavaScript has several built-in iterators, such as the Array iterator, Map iterator, and Set iterator. You can use methods like forEach, map, and filter to work with these iterators.

How do I use the for...of loop with iterators?

The for...of loop is a great way to iterate over iterable objects. For example:

const array = [1, 2, 3];
for (const value of array) {
    console.log(value);
}
// Output: 1, 2, 3