HIDDevice: collections property
Limited availability
This feature is not Baseline because it does not work in some of the most widely-used browsers.
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The collections
read-only property of the 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
to0x7F
-
Reserved for future use
0x80
to0xFF
-
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
Specification |
---|
WebHID API # dom-hiddevice-collections |
Browser compatibility
BCD tables only load in the browser