Generator function and for..of statement in JavaScript

Published August 11, 2020

Suppose we have a generator function which returns the even numbers from 0 to 100.

// Even Numbers Generator Function
function* EvenNumberGen() {
  for (let i = 0; i <= 100; i++) {
    if (i % 2 === 0) {
      yield i;
    } else {
      continue;
    }
  }
}

Let's use this generator function with a for...of looping statement.

// Even Numbers Generator Function
function* EvenNumberGen() {
  for (let i = 0; i <= 100; i++) {
    if (i % 2 === 0) {
      yield i;
    } else {
      continue;
    }
  }
}

// using generator function inside
// a for...of looping statement.
for (let evenNumber of EvenNumberGen()) {
  console.log(evenNumber);
}

As you can see we never have to use the next() method and extract the value using the value property.

This is because generator functions are iterable by default. The next() method in the generator function is called automatically and the value property is extracted in the for...of looping statement.

Feel free to share if you found this useful 😃.


Share on: Facebook Twitter