update(extensions): Rename DraftStoreExtension and MessageStoreExtension

Summary:
- Rename DraftStoreExtension to ComposerExtension
- Rename MessageStoreExtension to MessageViewExtension
- Rename ContenteditablePlugin to ContenteditableExtension
  - Update Contenteditable to use new naming convention
  - Adds support for extension handlers as props
- Add ExtensionRegistry to register extensions:
  - ContenteditableExtensions will not be registered through the
    ExtensionRegistry. They are meant for internal use, or if anyone wants
    to use our Contenteditable component directly in their plugins.
  - Adds specs
- Refactors internal_packages and src to use new names and new ExtensionRegistry api
- Adds deprecation util function and deprecation notices for old api methods:
  - DraftStore.{registerExtension, unregisterExtension}
  - MessageStore.{registerExtension, unregisterExtension}
  - DraftStoreExtension.{onMouseUp, onTabDown}
  - MessageStoreExtension
- Adds and updates docs

Test Plan: - Unit tests

Reviewers: bengotow, evan

Reviewed By: evan

Differential Revision: https://phab.nylas.com/D2293

docs/ComposerExtensions.md

@@ -14,18 +14,18 @@ This API allows your package to:
 
 - Transform the draft and make additional changes before it is sent.
 
-To create your own composer extensions, subclass {DraftStoreExtensions} and override the methods your extension needs.
+To create your own composer extensions, subclass {ComposerExtension} and override the methods your extension needs.
 
-In the sample packages repository, [templates]() is an example of a package which uses a DraftStoreExtension to enhance the composer experience.
+In the sample packages repository, [templates]() is an example of a package which uses a ComposerExtension to enhance the composer experience.
 
 ### Example
 
 This extension displays a warning before sending a draft that contains the names of competitors' products. If the user proceeds to send the draft containing the words, it appends a disclaimer.
 
 ```coffee
-{DraftStoreExtension} = require 'nylas-exports'
+{ComposerExtension} = require 'nylas-exports'
 
-class ProductsExtension extends DraftStoreExtension
+class ProductsExtension extends ComposerExtension
 
    @warningsForSending: (draft) ->
       words = ['acme', 'anvil', 'tunnel', 'rocket', 'dynamite']

examples/N1-Composer-Templates/lib/template-draft-extension.es6

@@ -43,7 +43,6 @@ class TemplatesDraftStoreExtension extends DraftStoreExtension {
   }
 
   static onTabDown(editableNode, range, event) {
-    console.log('tabbed');
     if (event.shiftKey) {
       return this.onTabSelectNextVar(editableNode, range, event, -1);
     }

internal_packages/composer-signature/lib/main.coffee

@@ -1,5 +1,5 @@
-{PreferencesUIStore, DraftStore} = require 'nylas-exports'
-SignatureDraftExtension = require './signature-draft-extension'
+{PreferencesUIStore, ExtensionRegistry} = require 'nylas-exports'
+SignatureComposerExtension = require './signature-composer-extension'
 
 module.exports =
   activate: (@state={}) ->
@@ -8,11 +8,11 @@ module.exports =
       displayName: "Signatures"
       component: require "./preferences-signatures"
 
-    DraftStore.registerExtension(SignatureDraftExtension)
+    ExtensionRegistry.Composer.register(SignatureComposerExtension)
     PreferencesUIStore.registerPreferencesTab(@preferencesTab)
 
   deactivate: ->
-    DraftStore.unregisterExtension(SignatureDraftExtension)
+    ExtensionRegistry.Composer.unregister(SignatureComposerExtension)
     PreferencesUIStore.unregisterPreferencesTab(@preferencesTab.sectionId)
 
   serialize: -> @state

internal_packages/composer-signature/lib/signature-composer-extension.coffee

@@ -1,6 +1,6 @@
-{DraftStoreExtension, AccountStore} = require 'nylas-exports'
+{ComposerExtension, AccountStore} = require 'nylas-exports'
 
-class SignatureDraftStoreExtension extends DraftStoreExtension
+class SignatureComposerExtension extends ComposerExtension
   @prepareNewDraft: (draft) ->
     accountId = AccountStore.current().id
     signature = NylasEnv.config.get("nylas.account-#{accountId}.signature")
@@ -11,4 +11,4 @@ class SignatureDraftStoreExtension extends DraftStoreExtension
       insertionPoint = draft.body.length
     draft.body = draft.body.substr(0, insertionPoint-1) + "<br/>" + signature + draft.body.substr(insertionPoint)
 
-module.exports = SignatureDraftStoreExtension
+module.exports = SignatureComposerExtension

internal_packages/composer-signature/spec/signature-composer-extension-spec.coffee

@@ -1,8 +1,8 @@
 {Message} = require 'nylas-exports'
 
-SignatureDraftStoreExtension = require '../lib/signature-draft-extension'
+SignatureComposerExtension = require '../lib/signature-composer-extension'
 
-describe "SignatureDraftStoreExtension", ->
+describe "SignatureComposerExtension", ->
   describe "prepareNewDraft", ->
     describe "when a signature is defined", ->
       beforeEach ->
@@ -18,9 +18,9 @@ describe "SignatureDraftStoreExtension", ->
           draft: true
           body: 'This is a another test.'
 
-        SignatureDraftStoreExtension.prepareNewDraft(a)
+        SignatureComposerExtension.prepareNewDraft(a)
         expect(a.body).toEqual("This is a test!<br/><div id='signature'>This is my signature.</div><blockquote>Hello world</blockquote>")
-        SignatureDraftStoreExtension.prepareNewDraft(b)
+        SignatureComposerExtension.prepareNewDraft(b)
         expect(b.body).toEqual("This is a another test<br/><div id='signature'>This is my signature.</div>")
 
     describe "when a signature is not defined", ->
@@ -32,5 +32,5 @@ describe "SignatureDraftStoreExtension", ->
         a = new Message
           draft: true
           body: 'This is a test! <blockquote>Hello world</blockquote>'
-        SignatureDraftStoreExtension.prepareNewDraft(a)
+        SignatureComposerExtension.prepareNewDraft(a)
         expect(a.body).toEqual('This is a test! <blockquote>Hello world</blockquote>')

internal_packages/composer-spellcheck/lib/main.coffee

@@ -1,11 +1,11 @@
-{ComponentRegistry, DraftStore} = require 'nylas-exports'
-Extension = require './draft-extension'
+{ExtensionRegistry} = require 'nylas-exports'
+SpellcheckComposerExtension = require './spellcheck-composer-extension'
 
 module.exports =
   activate: (@state={}) ->
-    DraftStore.registerExtension(Extension)
+    ExtensionRegistry.Composer.register(SpellcheckComposerExtension)
 
   deactivate: ->
-    DraftStore.unregisterExtension(Extension)
+    ExtensionRegistry.Composer.unregister(SpellcheckComposerExtension)
 
   serialize: -> @state

internal_packages/composer-spellcheck/lib/spellcheck-composer-extension.coffee

@@ -1,4 +1,4 @@
-{DraftStoreExtension, AccountStore, DOMUtils} = require 'nylas-exports'
+{ComposerExtension, AccountStore, DOMUtils} = require 'nylas-exports'
 _ = require 'underscore'
 spellchecker = require('spellchecker')
 remote = require('remote')
@@ -6,16 +6,16 @@ MenuItem = remote.require('menu-item')
 
 SpellcheckCache = {}
 
-class SpellcheckDraftStoreExtension extends DraftStoreExtension
+class SpellcheckComposerExtension extends ComposerExtension
 
   @isMisspelled: (word) ->
     SpellcheckCache[word] ?= spellchecker.isMisspelled(word)
     SpellcheckCache[word]
 
-  @onInput: (editableNode) ->
+  @onInput: (editableNode) =>
     @walkTree(editableNode)
 
-  @onShowContextMenu: (event, editableNode, selection, innerStateProxy, menu) =>
+  @onShowContextMenu: (event, editableNode, selection, menu) =>
     range = DOMUtils.Mutating.getRangeAtAndSelectWord(selection, 0)
     word = range.toString()
     if @isMisspelled(word)
@@ -123,6 +123,6 @@ class SpellcheckDraftStoreExtension extends DraftStoreExtension
     if body != clean
       session.changes.add(body: clean)
 
-SpellcheckDraftStoreExtension.SpellcheckCache = SpellcheckCache
+SpellcheckComposerExtension.SpellcheckCache = SpellcheckCache
 
-module.exports = SpellcheckDraftStoreExtension
+module.exports = SpellcheckComposerExtension

internal_packages/composer-spellcheck/spec/spellcheck-composer-extension-spec.coffee

@@ -1,22 +1,22 @@
-SpellcheckDraftStoreExtension = require '../lib/draft-extension'
+SpellcheckComposerExtension = require '../lib/spellcheck-composer-extension'
 fs = require 'fs'
 _ = require 'underscore'
 
 initialHTML = fs.readFileSync(__dirname + '/fixtures/california-with-misspellings-before.html').toString()
 expectedHTML = fs.readFileSync(__dirname + '/fixtures/california-with-misspellings-after.html').toString()
 
-describe "SpellcheckDraftStoreExtension", ->
+describe "SpellcheckComposerExtension", ->
   beforeEach ->
     # Avoid differences between node-spellcheck on different platforms
     spellings = JSON.parse(fs.readFileSync(__dirname + '/fixtures/california-spelling-lookup.json'))
-    spyOn(SpellcheckDraftStoreExtension, 'isMisspelled').andCallFake (word) ->
+    spyOn(SpellcheckComposerExtension, 'isMisspelled').andCallFake (word) ->
       spellings[word]
 
   describe "walkTree", ->
     it "correctly walks a DOM tree and surrounds mispelled words", ->
       dom = document.createElement('div')
       dom.innerHTML = initialHTML
-      SpellcheckDraftStoreExtension.walkTree(dom)
+      SpellcheckComposerExtension.walkTree(dom)
       expect(dom.innerHTML).toEqual(expectedHTML)
 
   describe "finalizeSessionBeforeSending", ->
@@ -27,7 +27,7 @@ describe "SpellcheckDraftStoreExtension", ->
         changes:
           add: jasmine.createSpy('add')
 
-      SpellcheckDraftStoreExtension.finalizeSessionBeforeSending(session)
+      SpellcheckComposerExtension.finalizeSessionBeforeSending(session)
       expect(session.changes.add).toHaveBeenCalledWith(body: initialHTML)
 
-module.exports = SpellcheckDraftStoreExtension
+module.exports = SpellcheckComposerExtension

internal_packages/composer/lib/composer-extensions-plugin.coffee

@@ -1,27 +0,0 @@
-{DraftStore, DOMUtils, ContenteditablePlugin} = require 'nylas-exports'
-
-class ComposerExtensionsPlugin extends ContenteditablePlugin
-  @onInput: (event, editableNode, selection, innerStateProxy) ->
-    for extension in DraftStore.extensions()
-      extension.onInput?(editableNode, event)
-
-  @onKeyDown: (event, editableNode, selection, innerStateProxy) ->
-    if event.key is "Tab"
-      range = DOMUtils.getRangeInScope(editableNode)
-      for extension in DraftStore.extensions()
-        extension.onTabDown?(editableNode, range, event)
-
-  @onShowContextMenu: (args...) ->
-    for extension in DraftStore.extensions()
-      extension.onShowContextMenu?(args...)
-
-  @onClick: (event, editableNode, selection, innerStateProxy) ->
-    range = DOMUtils.getRangeInScope(editableNode)
-    return unless range
-    try
-      for extension in DraftStore.extensions()
-        extension.onMouseUp?(editableNode, range, event)
-    catch e
-      console.error('DraftStore extension raised an error: '+e.toString())
-
-module.exports = ComposerExtensionsPlugin

internal_packages/composer/lib/composer-view.cjsx

@@ -10,7 +10,8 @@ React = require 'react'
  AccountStore,
  FileUploadStore,
  QuotedHTMLParser,
- FileDownloadStore} = require 'nylas-exports'
+ FileDownloadStore,
+ ExtensionRegistry} = require 'nylas-exports'
 
 {DropZone,
  RetinaImg,
@@ -29,8 +30,6 @@ CollapsedParticipants = require './collapsed-participants'
 
 Fields = require './fields'
 
-ComposerExtensionsPlugin = require './composer-extensions-plugin'
-
 # The ComposerView is a unique React component because it (currently) is a
 # singleton. Normally, the React way to do things would be to re-render the
 # Composer with new props.
@@ -68,6 +67,7 @@ class ComposerView extends React.Component
       enabledFields: [] # Gets updated in @_initiallyEnabledFields
       showQuotedText: false
       uploads: FileUploadStore.uploadsForMessage(@props.draftClientId) ? []
+      extensions: ExtensionRegistry.Composer.extensions()
 
   componentWillMount: =>
     @_prepareForDraft(@props.draftClientId)
@@ -80,6 +80,7 @@ class ComposerView extends React.Component
     @_usubs = []
     @_usubs.push FileUploadStore.listen @_onFileUploadStoreChange
     @_usubs.push AccountStore.listen @_onAccountStoreChanged
+    @_usubs.push ExtensionRegistry.Composer.listen @_onExtensionsChanged
     @_applyFieldFocus()
 
   componentWillUnmount: =>
@@ -300,7 +301,7 @@ class ComposerView extends React.Component
       onScrollTo={@props.onRequestScrollTo}
       onFilePaste={@_onFilePaste}
       onScrollToBottom={@_onScrollToBottom()}
-      plugins={[ComposerExtensionsPlugin]}
+      extensions={@state.extensions}
       getComposerBoundingRect={@_getComposerBoundingRect}
       initialSelectionSnapshot={@_recoveredSelection} />
 
@@ -529,6 +530,9 @@ class ComposerView extends React.Component
     enabledFields.push Fields.Body
     return enabledFields
 
+  _onExtensionsChanged: =>
+    @setState extensions: ExtensionRegistry.Composer.extensions()
+
   # When the account store changes, the From field may or may not still
   # be in scope. We need to make sure to update our enabled fields.
   _onAccountStoreChanged: =>
@@ -685,7 +689,7 @@ class ComposerView extends React.Component
       warnings.push('without a body')
 
     # Check third party warnings added via DraftStore extensions
-    for extension in DraftStore.extensions()
+    for extension in @state.extensions
       continue unless extension.warningsForSending
       warnings = warnings.concat(extension.warningsForSending(draft))
 

internal_packages/message-autoload-images/lib/autoload-images-extension.coffee

@@ -1,7 +1,7 @@
 AutoloadImagesStore = require './autoload-images-store'
-{MessageStoreExtension} = require 'nylas-exports'
+{MessageViewExtension} = require 'nylas-exports'
 
-class AutoloadImagesExtension extends MessageStoreExtension
+class AutoloadImagesExtension extends MessageViewExtension
 
   @formatMessageBody: (message) ->
     if AutoloadImagesStore.shouldBlockImagesIn(message)

internal_packages/message-autoload-images/lib/main.coffee

@@ -1,5 +1,5 @@
 {ComponentRegistry,
- MessageStore,
+ ExtensionRegistry,
  WorkspaceStore} = require 'nylas-exports'
 
 AutoloadImagesExtension = require './autoload-images-extension'
@@ -10,12 +10,12 @@ module.exports =
 
   activate: (@state={}) ->
     # Register Message List Actions we provide globally
-    MessageStore.registerExtension(AutoloadImagesExtension)
+    ExtensionRegistry.MessageView.register AutoloadImagesExtension
     ComponentRegistry.register AutoloadImagesHeader,
       role: 'message:BodyHeader'
 
   deactivate: ->
-    MessageStore.unregisterExtension(AutoloadImagesExtension)
+    ExtensionRegistry.MessageView.unregister AutoloadImagesExtension
     ComponentRegistry.unregister(AutoloadImagesHeader)
 
   serialize: -> @state

internal_packages/message-list/lib/main.cjsx

@@ -1,7 +1,7 @@
 MessageList = require "./message-list"
 MessageToolbarItems = require "./message-toolbar-items"
 {ComponentRegistry,
- MessageStore,
+ ExtensionRegistry,
  WorkspaceStore} = require 'nylas-exports'
 
 {SidebarContactCard,
@@ -46,8 +46,8 @@ module.exports =
     ComponentRegistry.register ThreadToggleUnreadButton,
       role: 'message:Toolbar'
 
-    MessageStore.registerExtension(AutolinkerExtension)
-    MessageStore.registerExtension(TrackingPixelsExtension)
+    ExtensionRegistry.MessageView.register AutolinkerExtension
+    ExtensionRegistry.MessageView.register TrackingPixelsExtension
 
   deactivate: ->
     ComponentRegistry.unregister MessageList
@@ -59,7 +59,7 @@ module.exports =
     ComponentRegistry.unregister SidebarContactCard
     ComponentRegistry.unregister SidebarSpacer
     ComponentRegistry.unregister SidebarContactList
-    MessageStore.unregisterExtension(AutolinkerExtension)
-    MessageStore.unregisterExtension(TrackingPixelsExtension)
+    ExtensionRegistry.MessageView.unregister AutolinkerExtension
+    ExtensionRegistry.MessageView.unregister TrackingPixelsExtension
 
   serialize: -> @state

internal_packages/message-list/lib/plugins/autolinker-extension.coffee

@@ -1,7 +1,7 @@
 Autolinker = require 'autolinker'
-{MessageStoreExtension} = require 'nylas-exports'
+{MessageViewExtension} = require 'nylas-exports'
 
-class AutolinkerExtension extends MessageStoreExtension
+class AutolinkerExtension extends MessageViewExtension
 
   @formatMessageBody: (message) ->
     # Apply the autolinker pass to make emails and links clickable

internal_packages/message-list/lib/plugins/tracking-pixels-extension.coffee

@@ -1,4 +1,4 @@
-{MessageStoreExtension, RegExpUtils} = require 'nylas-exports'
+{MessageViewExtension, RegExpUtils} = require 'nylas-exports'
 
 TrackingBlacklist = [{
     name: 'Sidekick',
@@ -98,7 +98,7 @@ TrackingBlacklist = [{
     homepage: 'http://salesloft.com'
   }]
 
-class TrackingPixelsExtension extends MessageStoreExtension
+class TrackingPixelsExtension extends MessageViewExtension
 
   @formatMessageBody: (message) ->
     return unless message.isFromMe()

spec/extension-registry-spec.coffee

@@ -0,0 +1,63 @@
+ExtensionRegistry = require '../src/extension-registry'
+
+class TestExtension
+  @name: 'TestExtension'
+
+describe 'ExtensionRegistry', ->
+  beforeEach ->
+    @originalAdapters = ExtensionRegistry._deprecationAdapters
+    @registry = new ExtensionRegistry.Registry('Test')
+    spyOn @registry, 'triggerDebounced'
+
+  describe 'Registry', ->
+    it 'has trigger and listen to defined', ->
+      expect(@registry.trigger).toBeDefined()
+      expect(@registry.listen).toBeDefined()
+      expect(@registry.listenTo).toBeDefined()
+
+    describe 'register', ->
+      it 'throws an exception if extension not passed', ->
+        expect(=> @registry.register(null)).toThrow()
+
+      it 'throws an exception if extension does not have a name', ->
+        expect(=> @registry.register({})).toThrow()
+
+      it 'throws an exception if extension is array', ->
+        expect(=> @registry.register([])).toThrow()
+
+      it 'throws an exception if extension is string', ->
+        expect(=> @registry.register('')).toThrow()
+
+      it 'returns itself', ->
+        expect(@registry.register(TestExtension)).toBe(@registry)
+
+      it 'registers extension and triggers', ->
+        @registry.register(TestExtension)
+        expect(@registry.extensions().length).toEqual 1
+        expect(@registry.triggerDebounced).toHaveBeenCalled()
+
+      it 'does not add extensions with the same name', ->
+        expect(@registry.extensions().length).toEqual 0
+        @registry.register(TestExtension)
+        expect(@registry.extensions().length).toEqual 1
+        @registry.register({name: 'TestExtension'})
+        expect(@registry.extensions().length).toEqual 1
+
+      it 'calls deprecationAdapters if present for a role', ->
+        adapterSpy = jasmine.createSpy('adapterSpy').andCallFake (ext) -> ext
+        @registry = new ExtensionRegistry.Registry('Test', adapterSpy)
+        spyOn @registry, 'triggerDebounced'
+        @registry.register(TestExtension)
+        expect(adapterSpy.calls.length).toEqual 1
+
+    describe 'unregister', ->
+      it 'unregisters the extension if it exists', ->
+        @registry.register(TestExtension)
+        @registry.unregister(TestExtension)
+        expect(@registry.extensions().length).toEqual 0
+
+      it 'throws if invalid extension passed', ->
+        expect( => @registry.unregister('Test')).toThrow()
+        expect( => @registry.unregister(null)).toThrow()
+        expect( => @registry.unregister([])).toThrow()
+        expect( => @registry.unregister({})).toThrow()

spec/stores/draft-store-spec.coffee

@@ -6,7 +6,7 @@ ModelQuery = require '../../src/flux/models/query'
 AccountStore = require '../../src/flux/stores/account-store'
 DatabaseStore = require '../../src/flux/stores/database-store'
 DraftStore = require '../../src/flux/stores/draft-store'
-DraftStoreExtension = require '../../src/flux/stores/draft-store-extension'
+ComposerExtension = require '../../src/flux/extensions/composer-extension'
 SendDraftTask = require '../../src/flux/tasks/send-draft'
 DestroyDraftTask = require '../../src/flux/tasks/destroy-draft'
 SoundRegistry = require '../../src/sound-registry'
@@ -26,7 +26,7 @@ messageWithStyleTags = null
 fakeMessages = null
 fakeMessageWithFiles = null
 
-class TestExtension extends DraftStoreExtension
+class TestExtension extends ComposerExtension
   @prepareNewDraft: (draft) ->
     draft.body = "Edited by TestExtension!" + draft.body
 

src/component-registry.coffee

@@ -1,5 +1,4 @@
 _ = require 'underscore'
-Actions = require './flux/actions'
 
 {Listener, Publisher} = require './flux/modules/reflux-coffee'
 CoffeeHelpers = require './flux/coffee-helpers'

src/components/contenteditable/contenteditable-plugin.coffee

@@ -1,26 +0,0 @@
-###
-ContenteditablePlugin is an abstract base class. Implementations of this
-are used to make additional changes to a <Contenteditable /> component
-beyond a user's input intents.
-
-While some ContenteditablePlugins are included with the core
-<Contenteditable /> component, others may be added via the `plugins`
-prop.
-###
-class ContenteditablePlugin
-
-  # The onInput event can be triggered by a variety of events, some of
-  # which could have been already been looked at by a callback.
-  # Pretty much any DOM mutation will fire this.
-  # Sometimes those mutations are the cause of callbacks.
-  @onInput: (event, editableNode, selection, innerStateProxy) ->
-
-  @onBlur: (event, editableNode, selection, innerStateProxy) ->
-
-  @onFocus: (event, editableNode, selection, innerStateProxy) ->
-
-  @onClick: (event, editableNode, selection, innerStateProxy) ->
-
-  @onKeyDown: (event, editableNode, selection, innerStateProxy) ->
-
-  @onShowContextMenu: (event, editableNode, selection, innerStateProxy, menu) ->

src/components/contenteditable/contenteditable.cjsx

@@ -36,25 +36,34 @@ class Contenteditable extends React.Component
 
     initialSelectionSnapshot: React.PropTypes.object
 
-    # Passes an absolute top coordinate to scroll to.
+    # Handlers
     onChange: React.PropTypes.func.isRequired
     onFilePaste: React.PropTypes.func
+    # Passes an absolute top coordinate to scroll to.
     onScrollTo: React.PropTypes.func
     onScrollToBottom: React.PropTypes.func
 
-    # A list of objects that extend {ContenteditablePlugin}
-    plugins: React.PropTypes.array
+    # Extension DOM Mutating handlers. See {ContenteditableExtension}
+    onInput: React.PropTypes.func
+    onBlur: React.PropTypes.func
+    onFocus: React.PropTypes.func
+    onClick: React.PropTypes.func
+    onKeyDown: React.PropTypes.func
+    onShowContextMenu: React.PropTypes.func
+
+    # A list of objects that extend {ContenteditableExtension}
+    extensions: React.PropTypes.array
 
     spellcheck: React.PropTypes.bool
 
     floatingToolbar: React.PropTypes.bool
 
   @defaultProps:
-    plugins: []
+    extensions: []
     spellcheck: true
     floatingToolbar: true
 
-  corePlugins: [ListManager]
+  coreExtensions: [ListManager]
 
   # We allow extensions to read, and mutate the:
   #
@@ -70,7 +79,7 @@ class Contenteditable extends React.Component
     innerStateProxy =
       get: => return @innerState
       set: (newInnerState) => @setInnerState(newInnerState)
-    args = [event, @_editableNode(), document.getSelection(), innerStateProxy, extraArgs...]
+    args = [event, @_editableNode(), document.getSelection(), extraArgs..., innerStateProxy]
     editingFunction.apply(null, args)
     @_setupSelectionListeners()
 
@@ -162,7 +171,7 @@ class Contenteditable extends React.Component
     selection.addRange(range)
 
   # When some other component (like the `FloatingToolbar` or some
-  # `DraftStoreExtension`) wants to mutate the DOM, it declares a
+  # `ComposerExtension`) wants to mutate the DOM, it declares a
   # `mutator` function. That mutator expects to be passed the latest DOM
   # object (the `_editableNode()`) and will do mutations to it. Once those
   # mutations are done, we need to be sure to notify that changes
@@ -201,38 +210,42 @@ class Contenteditable extends React.Component
     @_setupSelectionListeners()
     @_onInput()
 
-  # Will execute the event handlers on each of the registerd and core plugins
+  # Will execute the event handlers on each of the registerd and core extensions
   # In this context, event.preventDefault and event.stopPropagation don't refer
   # to stopping default DOM behavior or prevent event bubbling through the DOM,
   # but rather prevent our own Contenteditable default behavior, and preventing
-  # other plugins from being called.
-  # If any of the plugins calls event.preventDefault() it will prevent the
+  # other extensions from being called.
+  # If any of the extensions calls event.preventDefault() it will prevent the
   # default behavior for the Contenteditable, which basically means preventing
-  # the core plugin handlers from being called.
-  # If any of the plugins calls event.stopPropagation(), it will prevent any
-  # other plugin handlers from being called.
+  # the core extension handlers from being called.
+  # If any of the extensions calls event.stopPropagation(), it will prevent any
+  # other extension handlers from being called.
   #
   # NOTE: It's possible for there to be no `event` passed in.
-  _runPluginHandlersForEvent: (method, event, args...) =>
-    executeCallback = (plugin) =>
-      return if not plugin[method]?
-      callback = plugin[method].bind(plugin)
+  _runExtensionHandlersForEvent: (method, event, args...) =>
+    executeCallback = (extension) =>
+      return if not extension[method]?
+      callback = extension[method].bind(extension)
       @atomicEdit(callback, event, args...)
 
-    for plugin in @props.plugins
+    # Check if any of the extension handlers where passed as a prop and call
+    # that first
+    executeCallback(@props)
+
+    for extension in @props.extensions
       break if event?.isPropagationStopped()
-      executeCallback(plugin)
+      executeCallback(extension)
 
     return if event?.defaultPrevented or event?.isPropagationStopped()
-    for plugin in @corePlugins
+    for extension in @coreExtensions
       break if event?.isPropagationStopped()
-      executeCallback(plugin)
+      executeCallback(extension)
 
   _onKeyDown: (event) =>
-    @_runPluginHandlersForEvent("onKeyDown", event)
+    @_runExtensionHandlersForEvent("onKeyDown", event)
 
     # This is a special case where we don't want to bubble up the event to the
-    # keymap manager if the plugin prevented the default behavior
+    # keymap manager if the extension prevented the default behavior
     if event.defaultPrevented
       event.stopPropagation()
       return
@@ -259,7 +272,7 @@ class Contenteditable extends React.Component
     @_ignoreInputChanges = true
     @_resetInnerStateOnInput()
 
-    @_runPluginHandlersForEvent("onInput", event)
+    @_runExtensionHandlersForEvent("onInput", event)
 
     @_normalize()
 
@@ -413,11 +426,12 @@ class Contenteditable extends React.Component
   _onBlur: (event) =>
     @setInnerState dragging: false
     return if @_editableNode().parentElement.contains event.relatedTarget
+    @_runExtensionHandlersForEvent("onBlur", event)
     @setInnerState editableFocused: false
 
   _onFocus: (event) =>
     @setInnerState editableFocused: true
-    @props.onFocus?(event)
+    @_runExtensionHandlersForEvent("onFocus", event)
 
   _editableNode: =>
     React.findDOMNode(@refs.contenteditable)
@@ -616,7 +630,8 @@ class Contenteditable extends React.Component
     MenuItem = remote.require('menu-item')
 
     menu = new Menu()
-    @_runPluginHandlersForEvent("onShowContextMenu", event, menu)
+
+    @_runExtensionHandlersForEvent("onShowContextMenu", event, menu)
     menu.append(new MenuItem({ label: 'Cut', role: 'cut'}))
     menu.append(new MenuItem({ label: 'Copy', role: 'copy'}))
     menu.append(new MenuItem({ label: 'Paste', role: 'paste'}))
@@ -660,7 +675,7 @@ class Contenteditable extends React.Component
     selection = document.getSelection()
     return event unless DOMUtils.selectionInScope(selection, editableNode)
 
-    @_runPluginHandlersForEvent("onClick", event)
+    @_runExtensionHandlersForEvent("onClick", event)
     return event
 
   _onDragStart: (event) =>

src/components/contenteditable/floating-toolbar.cjsx

@@ -3,7 +3,7 @@ React = require 'react/addons'
 classNames = require 'classnames'
 {CompositeDisposable} = require 'event-kit'
 {RetinaImg} = require 'nylas-component-kit'
-{DraftStore} = require 'nylas-exports'
+{ExtensionRegistry} = require 'nylas-exports'
 
 class FloatingToolbar extends React.Component
   @displayName = "FloatingToolbar"
@@ -29,9 +29,11 @@ class FloatingToolbar extends React.Component
     @state =
       urlInputValue: @_initialUrl() ? ""
       componentWidth: 0
+      extensions: ExtensionRegistry.Composer.extensions()
 
   componentDidMount: =>
     @subscriptions = new CompositeDisposable()
+    @usubExtensions = ExtensionRegistry.Composer.listen @_onExtensionsChanged
 
   componentWillReceiveProps: (nextProps) =>
     @setState
@@ -39,6 +41,7 @@ class FloatingToolbar extends React.Component
 
   componentWillUnmount: =>
     @subscriptions?.dispose()
+    @usubExtensions()
 
   componentDidUpdate: =>
     if @props.mode is "edit-link" and not @props.linkToModify
@@ -88,12 +91,12 @@ class FloatingToolbar extends React.Component
       <button className="btn btn-link toolbar-btn"
               onClick={@props.onClickLinkEditBtn}
               data-command-name="link"></button>
-      {@_toolbarExtensions()}
+      {@_toolbarExtensions(@state.extensions)}
     </div>
 
-  _toolbarExtensions: ->
+  _toolbarExtensions: (extensions) ->
     buttons = []
-    for extension in DraftStore.extensions()
+    for extension in extensions
       toolbarItem = extension.composerToolbar?()
       if toolbarItem
         buttons.push(
@@ -102,6 +105,9 @@ class FloatingToolbar extends React.Component
                 title="#{toolbarItem.tooltip}"><RetinaImg mode={RetinaImg.Mode.ContentIsMask} url="#{toolbarItem.iconUrl}" /></button>)
     return buttons
 
+  _onExtensionsChanged: =>
+    @setState extensions: ExtensionRegistry.Composer.extensions()
+
   _extensionMutateDom: (mutator) =>
     @props.onDomMutator(mutator)
 

src/components/contenteditable/list-manager.coffee

@@ -1,8 +1,7 @@
 _str = require 'underscore.string'
-{DOMUtils} = require 'nylas-exports'
-ContenteditablePlugin = require './contenteditable-plugin'
+{DOMUtils, ContenteditableExtension} = require 'nylas-exports'
 
-class ListManager extends ContenteditablePlugin
+class ListManager extends ContenteditableExtension
   @onInput: (event, editableNode, selection) ->
     if @_spaceEntered and @hasListStartSignature(selection)
       @createList(event, selection)

src/deprecate-utils.coffee

@@ -0,0 +1,21 @@
+_ = require 'underscore'
+
+class DeprecateUtils
+  @warn: (condition, message) ->
+    console.warn message if condition
+
+  @deprecate: (fnName, newName, ctx, fn) ->
+    if NylasEnv.inDevMode
+      warn = true
+      newFn = =>
+        DeprecateUtils.warn(
+          warn,
+          "Deprecation warning! #{fnName} is deprecated and will be removed soon.
+          Use #{newName} instead."
+        )
+        warn = false
+        return fn.apply(ctx, arguments)
+      return _.extend(newFn, fn)
+    return fn
+
+module.exports = DeprecateUtils

src/extension-registry.es6

@@ -0,0 +1,63 @@
+
+import _ from 'underscore';
+import {Listener, Publisher} from './flux/modules/reflux-coffee';
+import {includeModule} from './flux/coffee-helpers';
+
+export class Registry {
+
+  static include = includeModule;
+
+  constructor(name, deprecationAdapter = (ext)=> ext) {
+    this.name = name;
+    this._deprecationAdapter = deprecationAdapter;
+    this._registry = new Map();
+  }
+
+  register(extension) {
+    this.validateExtension(extension, 'register');
+    this._registry.set(extension.name, this._deprecationAdapter(extension));
+    this.triggerDebounced();
+    return this;
+  }
+
+  unregister(extension) {
+    this.validateExtension(extension, 'unregister');
+    this._registry.delete(extension.name);
+    this.triggerDebounced();
+  }
+
+  extensions() {
+    return Array.from(this._registry.values());
+  }
+
+  clear() {
+    this._registry = new Map();
+  }
+
+  triggerDebounced() {
+    _.debounce(()=> this.trigger(), 1);
+  }
+
+  validateExtension(extension, method) {
+    if (!extension || Array.isArray(extension) || !_.isObject(extension)) {
+      throw new Error(`ExtensionRegistry.${this.name}.${method} requires a valid \\
+                      extension object that implements one of the functions defined by ${this.name}Extension`);
+    }
+    if (!extension.name) {
+      throw new Error(`ExtensionRegistry.${this.name}.${method} requires a \\
+                      \`name\` property defined on the extension object`);
+    }
+  }
+}
+
+Registry.include(Publisher);
+Registry.include(Listener);
+
+export const Composer = new Registry(
+  'Composer',
+  require('./flux/extensions/composer-extension-adapter')
+);
+
+export const MessageView = new Registry(
+  'MessageView',
+);

src/flux/actions.coffee

@@ -296,7 +296,7 @@ class Actions
 
   ###
   Public: Send the draft with the given ID. This Action is handled by the {DraftStore},
-  which finalizes the {DraftChangeSet} and allows {DraftStoreExtension}s to display
+  which finalizes the {DraftChangeSet} and allows {ComposerExtension}s to display
   warnings and do post-processing. To change send behavior, you should consider using
   one of these objects rather than listening for the {sendDraft} action.
 

src/flux/extensions/composer-extension-adapter.coffee

@@ -0,0 +1,51 @@
+_ = require 'underscore'
+{deprecate} = require '../../deprecate-utils'
+DOMUtils = require '../../dom-utils'
+
+ComposerExtensionAdapter = (extension) ->
+
+  if extension.onInput?.length <= 2
+    origInput = extension.onInput
+    extension.onInput = (event, editableNode, selection) ->
+      origInput(editableNode, event)
+
+    extension.onInput = deprecate(
+      "DraftStoreExtension.onInput",
+      "ComposerExtension.onInput",
+      extension,
+      extension.onInput
+    )
+
+  if extension.onTabDown?
+    origKeyDown = extension.onKeyDown
+    extension.onKeyDown = (event, editableNode, selection) ->
+      if event.key is "Tab"
+        range = DOMUtils.getRangeInScope(editableNode)
+        extension.onTabDown(editableNode, range, event)
+      else
+        origKeyDown?(event, editableNode, selection)
+
+    extension.onKeyDown = deprecate(
+      "DraftStoreExtension.onTabDown",
+      "ComposerExtension.onKeyDown",
+      extension,
+      extension.onKeyDown
+    )
+
+  if extension.onMouseUp?
+    origOnClick = extension.onClick
+    extension.onClick = (event, editableNode, selection) ->
+      range = DOMUtils.getRangeInScope(editableNode)
+      extension.onMouseUp(editableNode, range, event)
+      origOnClick?(event, editableNode, selection)
+
+    extension.onClick = deprecate(
+      "DraftStoreExtension.onMouseUp",
+      "ComposerExtension.onClick",
+      extension,
+      extension.onClick
+    )
+
+  return extension
+
+module.exports = ComposerExtensionAdapter

src/flux/extensions/composer-extension.coffee

@@ -0,0 +1,109 @@
+###
+Public: To create ComposerExtensions that enhance the composer experience, you
+should create objects that implement the interface defined at {ComposerExtension}.
+
+{ComposerExtension} extends {ContenteditableExtension}, so you can also
+implement the methods defined there to further enhance the composer
+experience.
+
+To register your extension with the ExtensionRegistry, call {ExtensionRegistry::Composer::register}.
+When your package is being unloaded, you *must* call the corresponding
+{ExtensionRegistry::Composer::unregister} to unhook your extension.
+
+```coffee
+activate: ->
+  ExtensionRegistry.Composer.register(MyExtension)
+
+...
+
+deactivate: ->
+  ExtensionRegistry.Composer.unregister(MyExtension)
+```
+
+Your ComposerExtension should be stateless. The user may have multiple drafts
+open at any time, and the methods of your ComposerExtension may be called for different
+drafts at any time. You should not expect that the session you receive in
+ {::finalizeSessionBeforeSending} is for the same draft you previously received in
+ {::warningsForSending}, etc.
+
+The ComposerExtension API does not currently expose any asynchronous or {Promise}-based APIs.
+This will likely change in the future. If you have a use-case for a ComposerExtension that
+is not possible with the current API, please let us know.
+
+Section: Extensions
+###
+class ComposerExtension
+
+  ###
+  Public: Inspect the draft, and return any warnings that need to be displayed before
+  the draft is sent. Warnings should be string phrases, such as "without an attachment"
+  that fit into a message of the form: "Send #{phase1} and #{phase2}?"
+
+  - `draft`: A fully populated {Message} object that is about to be sent.
+
+  Returns a list of warning strings, or an empty array if no warnings need to be displayed.
+  ###
+  @warningsForSending: (draft) ->
+    []
+
+  ###
+  Public: declare an icon to be displayed in the composer's toolbar (where
+  bold, italic, underline, etc are).
+
+  You must return an object that contains the following properties:
+
+  - `mutator`: A function that's called when your toolbar button is
+  clicked. This mutator function will be passed as its only argument the
+  `dom`. The `dom` is the full {DOM} object of the current composer. You
+  may mutate this in place. We don't care about the mutator's return
+  value.
+
+  - `tooltip`: A one or two word description of what your icon does
+
+  - `iconUrl`: The url of your icon. It should be in the `nylas://` scheme.
+
+  For example: `nylas://your-package-name/assets/my-icon@2x.png`. Note, we
+  will downsample your image by 2x (for Retina screens), so make sure it's
+  twice the resolution. The icon should be black and white. We will
+  directly pass the `url` prop of a {RetinaImg}
+  ###
+  @composerToolbar: ->
+    return
+
+  ###
+  Public: Override prepareNewDraft to modify a brand new draft before it is displayed
+  in a composer. This is one of the only places in the application where it's safe
+  to modify the draft object you're given directly to add participants to the draft,
+  add a signature, etc.
+
+  By default, new drafts are considered `pristine`. If the user leaves the composer
+  without making any changes, the draft is discarded. If your extension populates
+  the draft in a way that makes it "populated" in a valuable way, you should set
+  `draft.pristine = false` so the draft saves, even if no further changes are made.
+  ###
+  @prepareNewDraft: (draft) ->
+    return
+
+  ###
+  Public: Override finalizeSessionBeforeSending in your ComposerExtension subclass to
+  transform the {DraftStoreProxy} editing session just before the draft is sent. This method
+  gives you an opportunity to make any final substitutions or changes after any
+  {::warningsForSending} have been displayed.
+
+  - `session`: A {DraftStoreProxy} for the draft.
+
+  Example:
+
+  ```coffee
+  # Remove any <code> tags found in the draft body
+  finalizeSessionBeforeSending: (session) ->
+    body = session.draft().body
+    clean = body.replace(/<\/?code[^>]*>/g, '')
+    if body != clean
+      session.changes.add(body: clean)
+  ```
+  ###
+  @finalizeSessionBeforeSending: (session) ->
+    return
+
+module.exports = ComposerExtension

src/flux/extensions/contenteditable-extension.coffee

@@ -0,0 +1,146 @@
+###
+Public: ContenteditableExtension is an abstract base class. Implementations of this
+are used to make additional changes to a <Contenteditable /> component
+beyond a user's input intents. The hooks in this class provide the contenteditable
+DOM Node itself, allowing you to adjust selection ranges and change content
+as necessary.
+
+While some ContenteditableExtension are included with the core
+<{Contenteditable} /> component, others may be added via the `plugins`
+prop when you use it inside your own components.
+
+Example:
+
+```javascript
+render() {
+  return(
+    <div>
+      <Contenteditable extensions={[MyAwesomeExtension]}>
+    </div>
+  );
+}
+```
+
+If you specifically want to enhance the Composer experience you should register
+a {ComposerExtension}
+
+Section: Extensions
+###
+class ContenteditableExtension
+
+  ###
+  Public: Override onInput in your Contenteditable subclass to implement custom
+  behavior as the user types in the contenteditable's body field. You may mutate
+  the contenteditable in place, we do not expect any return value from this method.
+
+  The onInput event can be triggered by a variety of events, some of which could
+  have been already been looked at by a callback. Almost any DOM mutation will
+  fire this event. Sometimes those mutations are the cause of other callbacks.
+
+  - event: DOM event fired on the contenteditable
+  - editableNode: DOM node that represents the current contenteditable.This object
+  can be mutated in place to modify the Contenteditable's content
+  - selection: [Selection](https://developer.mozilla.org/en-US/docs/Web/API/Selection)
+  object that represents the current selection on the contenteditable
+
+  Example:
+
+  The Nylas `templates` package uses this method to see if the user has populated a
+  `<code>` tag placed in the body and change it's CSS class to reflect that it is no
+  longer empty.
+
+  ```coffee
+  onInput: (event, editableNode, selection) ->
+    isWithinNode = (node) ->
+      test = selection.baseNode
+      while test isnt editableNode
+        return true if test is node
+        test = test.parentNode
+      return false
+
+    codeTags = editableNode.querySelectorAll('code.var.empty')
+    for codeTag in codeTags
+      if selection.containsNode(codeTag) or isWithinNode(codeTag)
+        codeTag.classList.remove('empty')
+  ```
+  ###
+  @onInput: (event, editableNode, selection) ->
+
+  ###
+  Public: Override onBlur to mutate the contenteditable DOM node whenever the
+  onBlur event is fired on it. You may mutate the contenteditable in place, we
+  not expect any return value from this method.
+
+  - event: DOM event fired on the contenteditable
+  - editableNode: DOM node that represents the current contenteditable.This object
+  can be mutated in place to modify the Contenteditable's content
+  - selection: [Selection](https://developer.mozilla.org/en-US/docs/Web/API/Selection)
+  object that represents the current selection on the contenteditable
+  ###
+  @onBlur: (event, editableNode, selection) ->
+
+  ###
+  Public: Override onFocus to mutate the contenteditable DOM node whenever the
+  onFocus event is fired on it. You may mutate the contenteditable in place, we
+  not expect any return value from this method.
+
+  - event: DOM event fired on the contenteditable
+  - editableNode: DOM node that represents the current contenteditable.This object
+  can be mutated in place to modify the Contenteditable's content
+  - selection: [Selection](https://developer.mozilla.org/en-US/docs/Web/API/Selection)
+  object that represents the current selection on the contenteditable
+  ###
+  @onFocus: (event, editableNode, selection) ->
+
+  ###
+  Public: Override onClick to mutate the contenteditable DOM node whenever the
+  onClick event is fired on it. You may mutate the contenteditable in place, we
+  not expect any return value from this method.
+
+  - event: DOM event fired on the contenteditable
+  - editableNode: DOM node that represents the current contenteditable.This object
+  can be mutated in place to modify the Contenteditable's content
+  - selection: [Selection](https://developer.mozilla.org/en-US/docs/Web/API/Selection)
+  object that represents the current selection on the contenteditable
+  ###
+  @onClick: (event, editableNode, selection) ->
+
+  ###
+  Public: Override onKeyDown to mutate the contenteditable DOM node whenever the
+  onKeyDown event is fired on it.
+  Public: Called when the user presses a key while focused on the contenteditable's body field.
+  Override onKeyDown in your ContenteditableExtension to adjust the selection or
+  perform other actions.
+
+  If your package implements key down behavior for a particular scenario, you
+  should prevent the default behavior of the key via `event.preventDefault()`.
+  You may mutate the contenteditable in place, we not expect any return value
+  from this method.
+
+  Important: You should prevent the default key down behavior with great care.
+
+  - event: DOM event fired on the contenteditable
+  - editableNode: DOM node that represents the current contenteditable.This object
+  can be mutated in place to modify the Contenteditable's content
+  - selection: [Selection](https://developer.mozilla.org/en-US/docs/Web/API/Selection)
+  object that represents the current selection on the contenteditable
+  ###
+  @onKeyDown: (event, editableNode, selection) ->
+
+  ###
+  Public: Override onInput to mutate the contenteditable DOM node whenever the
+  onInput event is fired on it.You may mutate the contenteditable in place, we
+  not expect any return value from this method.
+
+  - event: DOM event fired on the contenteditable
+  - editableNode: DOM node that represents the current contenteditable.This object
+  can be mutated in place to modify the Contenteditable's content
+  - selection: [Selection](https://developer.mozilla.org/en-US/docs/Web/API/Selection)
+  object that represents the current selection on the contenteditable
+  - menu: [Menu](https://github.com/atom/electron/blob/master/docs/api/menu.md)
+  object you can mutate in order to add new [MenuItems](https://github.com/atom/electron/blob/master/docs/api/menu-item.md)
+  to the context menu that will be displayed when you right click the contenteditable.
+  ###
+  @onShowContextMenu: (event, editableNode, selection, menu) ->
+
+module.exports = ContenteditableExtension

src/flux/extensions/message-view-extension.coffee

@@ -0,0 +1,34 @@
+###
+Public: To create MessageViewExtension that customize message viewing, you
+should create objects that implement the interface defined at {MessageViewExtension}.
+
+To register your extension with the ExtensionRegistry, call {ExtensionRegistry::MessageView::registerExtension}.
+When your package is being unloaded, you *must* call the corresponding
+{ExtensionRegistry::MessageView::unregisterExtension} to unhook your extension.
+
+```coffee
+activate: ->
+  ExtensionRegistry.MessageView.register(MyExtension)
+
+...
+
+deactivate: ->
+  ExtensionRegistry.MessageView.unregister(MyExtension)
+```
+
+The MessageViewExtension API does not currently expose any asynchronous or {Promise}-based APIs.
+This will likely change in the future. If you have a use-case for a Message Store extension that
+is not possible with the current API, please let us know.
+
+Section: Extensions
+###
+class MessageViewExtension
+
+  ###
+  Public: Transform the message body HTML provided in `body` and return HTML
+  that should be displayed for the message.
+  ###
+  @formatMessageBody: (body) ->
+    return body
+
+module.exports = MessageViewExtension

src/flux/stores/draft-store-extension.coffee

@@ -1,174 +1,7 @@
 ###
-Public: DraftStoreExtension is an abstract base class. To create DraftStoreExtensions
-that enhance the composer experience, you should subclass {DraftStoreExtension} and
-implement the class methods your plugin needs.
-
-To register your extension with the DraftStore, call {DraftStore::registerExtension}.
-When your package is being unloaded, you *must* call the corresponding
-{DraftStore::unregisterExtension} to unhook your extension.
-
-```coffee
-activate: ->
-  DraftStore.registerExtension(MyExtension)
-
-...
-
-deactivate: ->
-  DraftStore.unregisterExtension(MyExtension)
-```
-
-Your DraftStoreExtension subclass should be stateless. The user may have multiple drafts
-open at any time, and the methods of your DraftStoreExtension may be called for different
-drafts at any time. You should not expect that the session you receive in
- {::finalizeSessionBeforeSending} is for the same draft you previously received in
- {::warningsForSending}, etc.
-
-The DraftStoreExtension API does not currently expose any asynchronous or {Promise}-based APIs.
-This will likely change in the future. If you have a use-case for a Draft Store extension that
-is not possible with the current API, please let us know.
-
-Section: Drafts
+Public: DraftStoreExtension is deprecated. Use {ComposerExtension} instead.
+Section: Extensions
 ###
 class DraftStoreExtension
 
-  ###
-  Public: Inspect the draft, and return any warnings that need to be displayed before
-  the draft is sent. Warnings should be string phrases, such as "without an attachment"
-  that fit into a message of the form: "Send #{phase1} and #{phase2}?"
-
-  - `draft`: A fully populated {Message} object that is about to be sent.
-
-  Returns a list of warning strings, or an empty array if no warnings need to be displayed.
-  ###
-  @warningsForSending: (draft) ->
-    []
-
-  ###
-  Public: declare an icon to be displayed in the composer's toolbar (where
-  bold, italic, underline, etc are).
-
-  You must declare the following properties:
-
-  - `mutator`: A function that's called when your toolbar button is
-  clicked. This mutator function will be passed as its only argument the
-  `dom`. The `dom` is the full {DOM} object of the current composer. You
-  may mutate this in place. We don't care about the mutator's return
-  value.
-
-  - `tooltip`: A one or two word description of what your icon does
-
-  - `iconUrl`: The url of your icon. It should be in the `nylas://` scheme.
-  For example: `nylas://your-package-name/assets/my-icon@2x.png`. Note, we
-  will downsample your image by 2x (for Retina screens), so make sure it's
-  twice the resolution. The icon should be black and white. We will
-  directly pass the `url` prop of a {RetinaImg}
-  ###
-  @composerToolbar: ->
-    return
-
-  ###
-  Public: Override prepareNewDraft to modify a brand new draft before it is displayed
-  in a composer. This is one of the only places in the application where it's safe
-  to modify the draft object you're given directly to add participants to the draft,
-  add a signature, etc.
-
-  By default, new drafts are considered `pristine`. If the user leaves the composer
-  without making any changes, the draft is discarded. If your extension populates
-  the draft in a way that makes it "populated" in a valuable way, you should set
-  `draft.pristine = false` so the draft saves, even if no further changes are made.
-  ###
-  @prepareNewDraft: (draft) ->
-    return
-
-  ###
-  Public: Override finalizeSessionBeforeSending in your DraftStoreExtension subclass to transform
-  the {DraftStoreProxy} editing session just before the draft is sent. This method
-  gives you an opportunity to make any final substitutions or changes after any
-  {::warningsForSending} have been displayed.
-
-  - `session`: A {DraftStoreProxy} for the draft.
-
-  Example:
-
-  ```coffee
-  # Remove any <code> tags found in the draft body
-  finalizeSessionBeforeSending: (session) ->
-    body = session.draft().body
-    clean = body.replace(/<\/?code[^>]*>/g, '')
-    if body != clean
-      session.changes.add(body: clean)
-  ```
-  ###
-  @finalizeSessionBeforeSending: (session) ->
-    return
-
-  ###
-  Public: Override onMouseUp in your DraftStoreExtension subclass to
-  listen for mouse up events sent to the composer's body text area. This
-  hook provides the contenteditable DOM Node itself, allowing you to
-  adjust selection ranges and change content as necessary.
-
-  - `editableNode` The composer's contenteditable {Node}
-    that received the event.
-
-  - `range`: The currently selected {Range} in the `editableNode`
-
-  - `event`: The mouse up event.
-  ###
-  @onMouseUp: (editableNode, range, event) ->
-    return
-
-  ###
-  Public: Called when the user presses `Tab` while focused on the composer's body field.
-  Override onTabDown in your DraftStoreExtension to adjust the selection or perform
-  other actions. If your package implements Tab behavior in a particular scenario, you
-  should prevent the default behavior of Tab via `event.preventDefault()`.
-
-  Important: You should prevent the default tab behavior with great care.
-
-  - `editableNode` The composer's contenteditable {Node} that received the event.
-
-  - `range`: The currently selected {Range} in the `editableNode`
-
-  - `event`: The mouse up event.
-
-  ###
-  @onTabDown: (editableNode, range, event) ->
-    return
-
-  ###
-  Public: Override onInput in your DraftStoreExtension subclass to
-  implement custom behavior as the user types in the composer's
-  contenteditable body field.
-
-  As the first argument you are passed the entire DOM object of the
-  composer. You may mutate this object and edit it in place.
-
-  Example:
-
-  The Nylas `templates` package uses this method to see if the user has populated a
-  `<code>` tag placed in the body and change it's CSS class to reflect that it is no
-  longer empty.
-
-  ```coffee
-  onInput: (editableNode, event) ->
-    selection = document.getSelection()
-
-    isWithinNode = (node) ->
-      test = selection.baseNode
-      while test isnt editableNode
-        return true if test is node
-        test = test.parentNode
-      return false
-
-    codeTags = editableNode.querySelectorAll('code.var.empty')
-    for codeTag in codeTags
-      if selection.containsNode(codeTag) or isWithinNode(codeTag)
-        codeTag.classList.remove('empty')
-  ```
-
-  ###
-  @onInput: (editableNode, event) ->
-    return
-
 module.exports = DraftStoreExtension

src/flux/stores/draft-store.coffee

@@ -29,6 +29,9 @@ CoffeeHelpers = require '../coffee-helpers'
 DOMUtils = require '../../dom-utils'
 RegExpUtils = require '../../regexp-utils'
 
+ExtensionRegistry = require '../../extension-registry'
+{deprecate} = require '../../deprecate-utils'
+
 ###
 Public: DraftStore responds to Actions that interact with Drafts and exposes
 public getter methods to return Draft objects and sessions.
@@ -72,7 +75,6 @@ class DraftStore
     NylasEnv.onBeforeUnload @_onBeforeUnload
 
     @_draftSessions = {}
-    @_extensions = []
 
     @_inlineStylePromises = {}
     @_inlineStyleResolvers = {}
@@ -131,23 +133,25 @@ class DraftStore
 
   # Public: Returns the extensions registered with the DraftStore.
   extensions: =>
-    @_extensions
+    ExtensionRegistry.Composer.extensions()
 
-  # Public: Registers a new extension with the DraftStore. DraftStore extensions
+  # Public: Deprecated, use {ExtensionRegistry.Composer.register} instead.
+  # Registers a new extension with the DraftStore. DraftStore extensions
   # make it possible to extend the editor experience, modify draft contents,
   # display warnings before draft are sent, and more.
   #
-  # - `ext` A {DraftStoreExtension} instance.
+  # - `ext` A {ComposerExtension} instance.
   #
   registerExtension: (ext) =>
-    @_extensions.push(ext)
+    ExtensionRegistry.Composer.register(ext)
 
-  # Public: Unregisters the extension provided from the DraftStore.
+  # Public: Deprecated, use {ExtensionRegistry.Composer.unregister} instead.
+  # Unregisters the extension provided from the DraftStore.
   #
-  # - `ext` A {DraftStoreExtension} instance.
+  # - `ext` A {ComposerExtension} instance.
   #
   unregisterExtension: (ext) =>
-    @_extensions = _.without(@_extensions, ext)
+    ExtensionRegistry.Composer.unregister(ext)
 
   ########### PRIVATE ####################################################
 
@@ -228,7 +232,7 @@ class DraftStore
 
   _finalizeAndPersistNewMessage: (draft) =>
     # Give extensions an opportunity to perform additional setup to the draft
-    for extension in @_extensions
+    for extension in @extensions()
       continue unless extension.prepareNewDraft
       extension.prepareNewDraft(draft)
 
@@ -516,7 +520,7 @@ class DraftStore
 
   # Give third-party plugins an opportunity to sanitize draft data
   _runExtensionsBeforeSend: (session) ->
-    for extension in @_extensions
+    for extension in @extensions()
       continue unless extension.finalizeSessionBeforeSending
       extension.finalizeSessionBeforeSending(session)
 
@@ -537,4 +541,19 @@ class DraftStore
         NylasEnv.showErrorDialog(errorMessage)
       , 100
 
- module.exports = new DraftStore()
+
+# Deprecations
+store = new DraftStore()
+store.registerExtension = deprecate(
+  'DraftStore.registerExtension',
+  'ExtensionRegistry.Composer.register',
+  store,
+  store.registerExtension
+)
+store.unregisterExtension = deprecate(
+  'DraftStore.unregisterExtension',
+  'ExtensionRegistry.Composer.unregister',
+  store,
+  store.unregisterExtension
+)
+module.exports = store

src/flux/stores/message-store-extension.coffee

@@ -1,35 +1,7 @@
 ###
-Public: MessageStoreExtension is an abstract base class. To create MessageStoreExtension
-that customize message viewing, you should subclass {MessageStoreExtension} and
-implement the class methods your plugin needs.
-
-To register your extension with the MessageStore, call {MessageStore::registerExtension}.
-When your package is being unloaded, you *must* call the corresponding
-{MessageStore::unregisterExtension} to unhook your extension.
-
-```coffee
-activate: ->
-  MessageStore.registerExtension(MyExtension)
-
-...
-
-deactivate: ->
-  MessageStore.unregisterExtension(MyExtension)
-```
-
-The MessageStoreExtension API does not currently expose any asynchronous or {Promise}-based APIs.
-This will likely change in the future. If you have a use-case for a Message Store extension that
-is not possible with the current API, please let us know.
-
-Section: Stores
+Public: MessageStoreExtension is deprecated. Use {MessageViewExtension} instead.
+Section: Extensions
 ###
 class MessageStoreExtension
 
-  ###
-  Public: Transform the message body HTML provided in `body` and return HTML
-  that should be displayed for the message.
-  ###
-  @formatMessageBody: (body) ->
-    return body
-
 module.exports = MessageStoreExtension

src/flux/stores/message-store.coffee

@@ -8,6 +8,8 @@ AccountStore = require "./account-store"
 FocusedContentStore = require "./focused-content-store"
 ChangeUnreadTask = require '../tasks/change-unread-task'
 NylasAPI = require '../nylas-api'
+ExtensionRegistry = require '../../extension-registry'
+{deprecate} = require '../../deprecate-utils'
 async = require 'async'
 _ = require 'underscore'
 
@@ -43,25 +45,27 @@ class MessageStore extends NylasStore
 
   # Public: Returns the extensions registered with the MessageStore.
   extensions: =>
-    @_extensions
+    ExtensionRegistry.MessageView.extensions()
 
-  # Public: Registers a new extension with the MessageStore. MessageStore extensions
+  # Public: Deprecated, use {ExtensionRegistry.MessageView.register} instead.
+  # Registers a new extension with the MessageStore. MessageStore extensions
   # make it possible to customize message body parsing, and will do more in
   # the future.
   #
-  # - `ext` A {MessageStoreExtension} instance.
+  # - `ext` A {MessageViewExtension} instance.
   #
   registerExtension: (ext) =>
-    @_extensions.push(ext)
-    MessageBodyProcessor = require './message-body-processor'
-    MessageBodyProcessor.resetCache()
+    ExtensionRegistry.MessageView.register(ext)
 
-  # Public: Unregisters the extension provided from the MessageStore.
+  # Public: Deprecated, use {ExtensionRegistry.MessageView.unregister} instead.
+  # Unregisters the extension provided from the MessageStore.
   #
-  # - `ext` A {MessageStoreExtension} instance.
+  # - `ext` A {MessageViewExtension} instance.
   #
   unregisterExtension: (ext) =>
-    @_extensions = _.without(@_extensions, ext)
+    ExtensionRegistry.MessageView.unregister(ext)
+
+  _onExtensionsChanged: (role) ->
     MessageBodyProcessor = require './message-body-processor'
     MessageBodyProcessor.resetCache()
 
@@ -73,10 +77,10 @@ class MessageStore extends NylasStore
     @_itemsExpanded = {}
     @_itemsLoading = false
     @_thread = null
-    @_extensions = []
     @_inflight = {}
 
   _registerListeners: ->
+    @listenTo ExtensionRegistry.MessageView, @_onExtensionsChanged
     @listenTo DatabaseStore, @_onDataChanged
     @listenTo FocusedContentStore, @_onFocusChanged
     @listenTo Actions.toggleMessageIdExpanded, @_onToggleMessageIdExpanded
@@ -287,4 +291,17 @@ class MessageStore extends NylasStore
 
     items
 
-module.exports = new MessageStore()
+store = new MessageStore()
+store.registerExtension = deprecate(
+  'MessageStore.registerExtension',
+  'ExtensionRegistry.MessageView.register',
+  store,
+  store.registerExtension
+)
+store.unregisterExtension = deprecate(
+  'MessageStore.unregisterExtension',
+  'ExtensionRegistry.MessageView.unregister',
+  store,
+  store.unregisterExtension
+)
+module.exports = store

src/global/nylas-exports.coffee

@@ -33,6 +33,15 @@ class NylasExports
     NylasExports.registerSerializable(exported)
     @[prop] = exported
 
+  @requireDeprecated = (prop, path, {instead} = {}) ->
+    {deprecate} = require '../deprecate-utils'
+    Object.defineProperty @, prop,
+      get: deprecate prop, instead, @, ->
+        exported = require "../#{path}"
+        NylasExports.registerSerializable(exported)
+        return exported
+      enumerable: true
+
   # Actions
   @load "Actions", 'flux/actions'
 
@@ -108,14 +117,24 @@ class NylasExports
   @require "ThreadCountsStore", 'flux/stores/thread-counts-store'
   @require "UnreadBadgeStore", 'flux/stores/unread-badge-store'
   @require "FileDownloadStore", 'flux/stores/file-download-store'
-  @require "DraftStoreExtension", 'flux/stores/draft-store-extension'
   @require "FocusedContentStore", 'flux/stores/focused-content-store'
   @require "FocusedMailViewStore", 'flux/stores/focused-mail-view-store'
   @require "FocusedContactsStore", 'flux/stores/focused-contacts-store'
   @require "MessageBodyProcessor", 'flux/stores/message-body-processor'
-  @require "MessageStoreExtension", 'flux/stores/message-store-extension'
   @require "PreferencesUIStore", 'flux/stores/preferences-ui-store'
 
+  # Deprecated
+  @requireDeprecated "DraftStoreExtension", 'flux/stores/draft-store-extension',
+    instead: 'ComposerExtension'
+  @requireDeprecated "MessageStoreExtension", 'flux/stores/message-store-extension',
+    instead: 'MessageViewExtension'
+
+  # Extensions
+  @require "ExtensionRegistry", 'extension-registry'
+  @require "ContenteditableExtension", 'flux/extensions/contenteditable-extension'
+  @require "ComposerExtension", 'flux/extensions/composer-extension'
+  @require "MessageViewExtension", 'flux/extensions/message-view-extension'
+
   # React Components
   @get "React", -> require 'react' # Our version of React for 3rd party use
   @load "ReactRemote", 'react-remote/react-remote-parent'
@@ -146,9 +165,6 @@ class NylasExports
   @load "BufferedProcess", 'buffered-process'
   @get "APMWrapper", -> require('../apm-wrapper')
 
-  # Contenteditable
-  @load "ContenteditablePlugin", 'components/contenteditable/contenteditable-plugin'
-
   # Testing
   @get "NylasTestUtils", -> require '../../spec/nylas-test-utils'