WindowSharedStorage

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The WindowSharedStorage interface of the Shared Storage API represents the shared storage for a particular origin within a standard browsing context.

WindowSharedStorage is accessed via Window.sharedStorage.

Instance properties

worklet

Contains the SharedStorageWorklet instance representing the shared storage worklet for the current origin. SharedStorageWorklet includes the addModule() method, which is used to add a module to the shared storage worklet.

Instance methods

WindowSharedStorage inherits properties from its parent interface, SharedStorage.

run()

Executes a Run output gate operation that has been registered in a module added to the SharedStorageWorklet of the current origin.

selectURL()

Executes a URL Selection output gate operation that has been registered in a module added to the SharedStorageWorklet of the current origin.

Examples

js
// Randomly assigns a user to a group 0 or 1
function getExperimentGroup() {
  return Math.round(Math.random());
}

async function injectContent() {
  // Add the module to the shared storage worklet
  await window.sharedStorage.worklet.addModule("ab-testing-worklet.js");

  // Assign user to a random group (0 or 1) and store it in shared storage
  window.sharedStorage.set("ab-testing-group", getExperimentGroup(), {
    ignoreIfPresent: true,
  });

  // Run the URL selection operation
  const fencedFrameConfig = await window.sharedStorage.selectURL(
    "ab-testing",
    [
      { url: `https://your-server.example/content/default-content.html` },
      { url: `https://your-server.example/content/experiment-content-a.html` },
    ],
    {
      resolveToConfig: true,
    },
  );

  // Render the chosen URL into a fenced frame
  document.getElementById("content-slot").config = fencedFrameConfig;
}

injectContent();

See the Shared Storage API landing page for a walkthrough of this example and links to other examples.

Specifications

Specification
Shared Storage API
# windowsharedstorage

Browser compatibility

BCD tables only load in the browser

See also