Mailspring/static/package-template/lib/main.cjsx

{ComponentRegistry} = require 'nylas-exports'

MyComposerButton = require './my-composer-button'
MyMessageSidebar = require './my-message-sidebar'

module.exports =
  # Activate is called when the package is loaded. If your package previously
  # saved state using `serialize` it is provided.
  #
  activate: (@state) ->
    ComponentRegistry.register MyComposerButton,
      role: 'Composer:ActionButton'

    ComponentRegistry.register MyMessageSidebar,
      role: 'sidebar:focusedContactInfo'

  # Serialize is called when your package is about to be unmounted.
  # You can return a state object that will be passed back to your package
  # when it is re-activated.
  #
  serialize: ->

  # This **optional** method is called when the window is shutting down,
  # or when your package is being updated or disabled. If your package is
  # watching any files, holding external resources, providing commands or
  # subscribing to events, release them here.
  #
  deactivate: ->
    ComponentRegistry.unregister(MyComposerButton)
    ComponentRegistry.unregister(MyMessageSidebar)