Optional ReadonlydisplayChannels may be visualized and selectable by users. DisplayMetadata may be used to provide hints on how to see them. For App channels, displayMetadata would typically not be present.
ReadonlyidConstant that uniquely identifies this channel.
ReadonlytypeUniquely defines each channel type. Can be "user", "app" or "private".
Adds a listener for incoming contexts of the specified context type whenever a broadcast happens on this channel.
If, when this function is called, the channel already contains context that would be passed to the listener it is NOT called or passed this context automatically (this behavior differs from that of the fdc3.addContextListener function). Apps wishing to access to the current context of the channel should instead call the getCurrentContext(contextType) function.
Optional metadata about each context message received, including the app that originated the message, SHOULD be provided by the desktop agent implementation.
Broadcasts a context on the channel. This function can be used without first joining the channel, allowing applications to broadcast on both App Channels and User Channels that they aren't a member of.
If the broadcast is denied by the channel or the channel is not available, the promise will be rejected with an Error with a message string from the ChannelError enumeration.
Channel implementations should ensure that context messages broadcast by an application on a channel should not be delivered back to that same application if they are joined to the channel.
If you are working with complex context types composed of other simpler types (as recommended by the FDC3 Context Data specification) then you should broadcast each individual type (starting with the simpler types, followed by the complex type) that you want other apps to be able to respond to. Doing so allows applications to filter the context types they receive by adding listeners for specific context types.
If an application attempts to broadcast an invalid context argument the Promise returned by this function should reject with the ChannelError.MalformedContext error.
When a contextType_is provided, the most recent context matching the type will be returned, ornull` if no matching context is found.
If no contextType is provided, the most recent context that was broadcast on the channel - regardless of type - will be returned. If no context has been set on the channel, it will return null.
It is up to the specific Desktop Agent implementation whether and how recent contexts are stored. For example, an implementation could store context history for a channel in a single array and search through the array for the last context matching a provided type, or context could be maintained as a dictionary keyed by context types. An implementation could also choose not to support context history, in which case this method will return null for any context type not matching the type of the most recent context.
If getting the current context fails, the promise will be rejected with an Error with a message string from the ChannelError enumeration.
OptionalcontextType: string
Represents a context channel that applications can use to send and receive context data.
Please note that There are differences in behavior when you interact with a User channel via the
DesktopAgentinterface and theChannelinterface. Specifically, when 'joining' a User channel or adding a context listener when already joined to a channel via theDesktopAgentinterface, existing context (matching the type of the context listener) on the channel is received by the context listener immediately. Whereas, when a context listener is added via the Channel interface, context is not received automatically, but may be retrieved manually via thegetCurrentContext()function.