HIDDevice: collections property

{{securecontext_header}}{{APIRef("WebHID API")}}{{SeeCompatTable}}{{AvailableInWorkers("window_and_worker_except_shared")}}

The collections read-only property of the {{domxref("HIDDevice")}} interface returns an array of report formats

Value

An array of report formats. Each entry contains the following:

• usagePage

  • : An integer representing the usage page component of the HID usage associated with this collection. The usage for a top level collection is used to identify the device type.

    Standard HID usage values can be found in the HID Usage Tables document

• usage

  • : An integer representing the usage ID component of the HID usage associated with this collection.

• type

  • : An 8-bit value representing the collection type, which describes a different relationship between the grouped items. One of:

    • 0x00
      • : Physical (group of axes)
    • 0x01
      • : Application (mouse, keyboard)
    • 0x02
      • : Logical (interrelated data)
    • 0x03
      • : Report
    • 0x04
      • : Named array
    • 0x05
      • : Usage switch
    • 0x06
      • : Usage modified
    • 0x07 to 0x7F
      • : Reserved for future use
    • 0x80 to 0xFF
      • : Vendor-defined

    More information on these types can be found in the Device Class Definition document.

• children

  • : An array of sub-collections which takes the same format as a top-level collection.

• inputReports

  • : An array of inputReport items which represent individual input reports described in this collection.

• outputReports

  • : An array of outputReport items which represent individual output reports described in this collection.

• featureReports

  • : An array of featureReport items which represent individual feature reports described in this collection.

Examples

The following example demonstrates how to access the various elements once the collections property has been returned. You can see more examples, and live demos in the article Connecting to uncommon HID devices.

for (const collection of device.collections) {
  // A HID collection includes usage, usage page, reports, and subcollections.
  console.log(`Usage: ${collection.usage}`);
  console.log(`Usage page: ${collection.usagePage}`);

  for (const inputReport of collection.inputReports) {
    console.log(`Input report: ${inputReport.reportId}`);
    // Loop through inputReport.items
  }

  for (const outputReport of collection.outputReports) {
    console.log(`Output report: ${outputReport.reportId}`);
    // Loop through outputReport.items
  }

  for (const featureReport of collection.featureReports) {
    console.log(`Feature report: ${featureReport.reportId}`);
    // Loop through featureReport.items
  }

  // Loop through subcollections with collection.children
}

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}