ContentIndex: getAll() method

This method receives no parameters.

Returns a Promise that resolves with an Array of contentDescription items.

contentDescription

Each item returned is an Object containing the following data:

id

A unique String identifier.

title

A String title of the item. Used in user-visible lists of content.

description

A String description of the item. Used in user-visible lists of content.

url

A String containing the URL of the corresponding HTML document. Needs to be under the scope of the current service worker.

category Optional

A String defining the category of content. Can be:

• '' An empty String, this is the default.
• homepage
• article
• video
• audio

icons Optional

An Array of image resources, defined as an Object with the following data:

src

A URL String of the source image.

sizes Optional

A String representation of the image size.

type Optional

The MIME type of the image.

label Optional

A string representing the accessible name of the icon.

No exceptions are thrown. If there are no items in the Content Index, an empty Array is returned.

The below example shows an asynchronous function that retrieves items within the content index and iterates over each entry, building a list for the interface.

async function createReadingList() {
  // access our service worker registration
  const registration = await navigator.serviceWorker.ready;

  // get our index entries
  const entries = await registration.index.getAll();

  // create a containing element
  const readingListElem = document.createElement("div");

  // test for entries
  if (entries.length === 0) {
    // if there are no entries, display a message
    const message = document.createElement("p");
    message.innerText =
      "You currently have no articles saved for offline reading.";

    readingListElem.append(message);
  } else {
    // if entries are present, display in a list of links to the content
    const listElem = document.createElement("ul");

    for (const entry of entries) {
      const listItem = document.createElement("li");

      const anchorElem = document.createElement("a");
      anchorElem.innerText = entry.title;
      anchorElem.setAttribute("href", entry.url);

      listElem.append(listItem);
    }

    readingListElem.append(listElem);
  }
}

• An introductory article on the Content Index API
• An app which uses the Content Index API to list and remove 'save for later' content
• Service Worker API, along with information about Cache and CacheStorage