What is the difference between an iterator function and a generator?

What is the difference between an iterator function and a generator?

An iterator function returns an object that implements the iterator protocol, while a generator is a special type of iterator defined with a function that uses the 'yield' keyword.

Can you give me an example of each?

Sure! An iterator function might look like this:

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

A generator function would look like this:

function* createGenerator(array) {
    for (let item of array) {
        yield item;
    }
}

What are the advantages of using generators?

Generators are more memory efficient because they yield values one at a time and only when requested, rather than storing all values in memory at once.

Are there any performance differences between them?

Yes, generators can be slower than iterator functions due to the overhead of maintaining the generator state, but they provide more flexibility and ease of use.