The ariaAtomic property of the ElementInternals interface reflects the value of the aria-atomic attribute, which indicates whether assistive technologies will present all, or only parts of, the changed region based on the change notifications defined by the aria-relevant attribute.

A string with one of the following values:

"false"

Assistive technologies will present only the changed node or nodes.

"true"

Assistive technologies will present the entire changed region as a whole, including the author-defined label if one exists.

In this example the value of ariaAtomic is set to "true" in the constructor for a custom element .

class MyCustomElement extends HTMLElement {
  constructor() {
    super();
    this.internals_ = this.attachInternals();
    this.internals_.ariaAtomic = "true";
  }
}