Event: composedPath() method

Syntax

composedPath()

Parameters

None.

Return value

An array of EventTarget objects representing the objects on which an event listener will be invoked.

Examples

In the following example, which you can try out at https://mdn.github.io/web-components-examples/composed-composed-path/, we define two trivial custom elements, <open-shadow> and <closed-shadow>, both of which take the contents of their text attribute and insert them into the element's shadow DOM as the text content of a <p> element. The only difference between the two is that their shadow roots are attached with their modes set to open and closed respectively.

customElements.define(
  "open-shadow",
  class extends HTMLElement {
    constructor() {
      super();

      const pElem = document.createElement("p");
      pElem.textContent = this.getAttribute("text");

      const shadowRoot = this.attachShadow({ mode: "open" });
      shadowRoot.appendChild(pElem);
    }
  },
);

customElements.define(
  "closed-shadow",
  class extends HTMLElement {
    constructor() {
      super();

      const pElem = document.createElement("p");
      pElem.textContent = this.getAttribute("text");

      const shadowRoot = this.attachShadow({ mode: "closed" });
      shadowRoot.appendChild(pElem);
    }
  },
);

We then insert one of each element into our page:

<open-shadow text="I have an open shadow root"></open-shadow>
<closed-shadow text="I have a closed shadow root"></closed-shadow>

Then include a click event listener on the <html> element:

document.querySelector("html").addEventListener("click", (e) => {
  console.log(e.composed);
  console.log(e.composedPath());
});

When you click on the <open-shadow> element and then the <closed-shadow> element, you'll notice two things. First, the composed property returns true because the click event is always able to propagate across shadow boundaries. Second, you'll notice a difference in the value of composedPath for the two elements. The <open-shadow> element's composed path is this:

Array [ p, ShadowRoot, open-shadow, body, html, HTMLDocument https://mdn.github.io/web-components-examples/composed-composed-path/, Window ]

Whereas the <closed-shadow> element's composed path is a follows:

Array [ closed-shadow, body, html, HTMLDocument https://mdn.github.io/web-components-examples/composed-composed-path/, Window ]

In the second case, the event listeners only propagate as far as the <closed-shadow> element itself, but not to the nodes inside the shadow boundary.

Specifications

Browser compatibility