JavaScript Symbol asyncIterator Property

JavaScript Symbol asyncIterator property is used to set an object as an async iterable. Iterable properties of this object can be iterated over using a for await...of loop.

An async iterable object is any object that returns a function that produces an AsyncIterator for its Symbol.asyncIterator property.

The Symbol.asyncIterator symbol is a built-in symbol that is used to access an object's @@asyncIterator method. 

Note: For an object to be an async iterable, it must have a Symbol.asyncIterator key.

Example codes for the above property are as follows:

Example 1:

const GFG = {
    async*[Symbol.asyncIterator]() {
        let i = 0;
        while (i < 10) {
            if (i % 3 == 0) {
            yield i;
        }
        i++;
    }
}

};

(async () => {
    for await (const x of GFG) {
    console.log(x);
    }
})();

Output: 

0
3
6
9

Example 2:

const myAsyncIterable = {

  async*[Symbol.asyncIterator]() {

      let i = 0;
      while (i < 5) {
        yield i++;
      }
  }
};

(async () => {
  for await (const num of myAsyncIterable) {
  console.log(num + "<br>");
  }
})();

Output

0
1
2
3
4

Browser Support: The browsers supported by JavaScript Symbol.asyncIterator Property are listed below:

• Google Chrome
• Firefox
• Edge
• Opera
• Safari

We have a complete list of Javascript symbols' properties and methods, to check those please go through the Javascript Symbol Complete Reference article.