messages.md

Messaging

To communicate with the browser-part of the extension, Enhancer for Nebula defines a few messages. These are also available for user scripts.

Request messages take the following form:

{
  type: string; // type of the event
  name: string; // unique identifier to reply to
  ... // event data
}

The reply will be of this form:

{
  type: string; // unique identifier specified as `name` in request
  err?: any;    // error data
  res?: any;    // success data
}

It can be assumed that only one of res and err will be set. Exactly one message will be sent with type set to the specified name (assuming a correct message).

Note that postMessage requires the data to be JSON; requests must be JSON.stringifyd and responses JSON.parsed.

Enhancer for Nebula will answer to events of the Message enum. An example of how to send messages can be found in sendMessage function.

It is recommended to follow the scheme of enhancer-message-... for the message name.

The handler for queue events is defined here, all other events are handled here. For more information on events, see Events.

Events

Currently, only one event is exposed from the browser part to the content part. To listen for the event, send a registerListener message with the event property set as per the events enum. Events work exactly the same as messages except that multiple messages are sent with the same type.

An example of how to listen to events can be found in sendEventHandler function.

It is recommended to follow the scheme of enhancer-event-... for the message name.