HIDDevice.collections

Secure context

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The collections read-only property of the HIDDevice interface returns an array of report formats

Syntax

let collections = HIDDevice.collections;

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

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

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

  // Loop through subcollections with collection.children
}

Specifications

Specification
WebHID API
# dom-hiddevice-collections

Browser compatibility

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