TheWorkletSharedStorage interface of theShared Storage API represents the shared storage for a particular origin within a worklet context.

WorkletSharedStorage is accessed viaSharedStorageWorkletGlobalScope.sharedStorage.

Instance properties

contextExperimentalNon-standard

Contains contextual data passed into the shared storage worklet from the associated browsing context via theFencedFrameConfig.setSharedStorageContext() method.

Instance methods

WorkletSharedStorage inherits properties from its parent interface,SharedStorage.

get()Experimental

Retrieves a value from the shared storage.

length()Experimental

Returns the number of entries currently stored in the shared storage for the current origin.

remainingBudget()Experimental

Returns the remaining navigation budget for the current origin.

WorkletSharedStorage also includes the following methods because it has anasync iterator defined on it:

entries()Experimental

Returns a new async iterator for the key-value pairs of aWorkletSharedStorage object instance's enumerable properties.

keys()Experimental

Returns a new async iterator containing the keys for each item in aWorkletSharedStorage object instance.

WorkletSharedStorage[Symbol.asyncIterator]()Experimental

Returns theentries() function by default.

Examples

Passing contextual data viasetSharedStorageContext()

You can use thePrivate Aggregation API to create reports that combine event-level data inside fenced frames with contextual data from the embedding document.setSharedStorageContext() can be used to pass contextual data from the embedder to shared storage worklets initiated by theProtected Audience API.

In this example, we store data from both the embedding page and the fenced frame usingshared storage.

On the embedding page, we set a mock event ID as the shared storage context usingsetSharedStorageContext():

const frameConfig = await navigator.runAdAuction({ resolveToConfig: true });// Data from the embedder that you want to pass to the shared storage workletframeConfig.setSharedStorageContext("some-event-id");const frame = document.createElement("fencedframe");frame.config = frameConfig;

Within the fenced frame, after adding the worklet module withwindow.sharedStorage.worklet.addModule(), we send the event-level data into the shared storage worklet module usingwindow.sharedStorage.run() (this is unrelated to the contextual data from the embedding document):

const frameData = {  // Data available only inside the fenced frame};await window.sharedStorage.worklet.addModule("reporting-worklet.js");await window.sharedStorage.run("send-report", {  data: {    frameData,  },});

In thereporting-worklet.js worklet, we read the embedding document's event ID fromsharedStorage.context and the frame's event-level data from the data object. We then report them through Private Aggregation:

class ReportingOperation {  convertEventIdToBucket(eventId) {    // …  }  convertEventPayloadToValue(info) {    // …  }  async run(data) {    // Data from the embedder    const eventId = sharedStorage.context;    // Data from the fenced frame    const eventPayload = data.frameData;    privateAggregation.sendHistogramReport({      bucket: convertEventIdToBucket(eventId),      value: convertEventPayloadToValue(eventPayload),    });  }}register("send-report", ReportingOperation);

Specifications

Browser compatibility

See also

• Shared Storage API