@mentions with trix-editor and selectize.js

mentionable_trix.js.coffee

window.addEventListener "trix-initialize", (e) =>
  Utility.TrixMentions.prepare($(e.target))

trix_mention_filter.rb

# Filter for use with https://github.com/jch/html-pipeline 
# to extract mentioned user_ids

module HTML
  class Pipeline
    class TrixMentionFilter < Filter
      attr_reader :mentioned_user_ids

      def initialize(doc, context = nil, result = nil)
        super doc, context, result
        @mentioned_user_ids = []
      end

      def call
        process_attachments! do |attachment|
          @mentioned_user_ids << attachment["user-id"].to_i
        end
        doc
      end

      def process_attachments!
        doc.css("[data-trix-attachment]").each do |attachment_node|
          attachment = JSON.parse(attachment_node.attribute('data-trix-attachment'))
          next unless attachment["attachment-type"] == "trix-mention"
          yield attachment
        end
      end
    end
  end
end

trix_mentions.js.coffee

window.Utility ||= {}

class Utility.TrixMentions
  MENTIONS_PATH = "mentions-path"
  MENTIONS_DIV_ID = "#trix-mentions-"
  MENTIONS_INPUT_ID = MENTIONS_DIV_ID + "input-"

  @prepare: ($trix) ->
    mentionsDivForTrix = ($trix) ->
      $(MENTIONS_DIV_ID + $trix.attr('trix-id'))

    mentionsInputForTrix = ($trix) ->
      $(MENTIONS_INPUT_ID + $trix.attr('trix-id'))

    mentionsSelectizeForTrix = ($trix) ->
      mentionsInputForTrix($trix).next('.selectize-control')

    mentionsSelectizeDropdownForTrix = ($trix) ->
      mentionsInputForTrix($trix).next('.selectize-dropdown')

    createMentionsDivForTrix = ($trix) ->
      $trix.after("<trix-mentions id='trix-mentions-"+  $trix.attr('trix-id') + "'><input id='trix-mentions-input-" + $trix.attr('trix-id') + "'></input></trix-mentions>")

    initializeMentionsSelectize = ($trix) ->
      $.getJSON $trix.data(MENTIONS_PATH), (result) ->
        mentionsInputForTrix($trix).selectize
          create: false
          valueField: 'id'
          labelField: 'name'
          searchField: 'name'
          sortField: 'name'
          options: result.data
          selectOnTab: true
          onInitialize: ->
            @.disable()
            mentionsSelectizeForTrix($trix).css('left', -1000)
          onItemAdd: (value, $item) ->
            embed = "<span class='trix-mention'>@" + $item.text() + "</span>"
            attachment = new Trix.Attachment
              content: embed
              'attachment-type': 'trix-mention'
              'user-id': $item.data('value')
            $trix[0].editor.setSelectedRange([$trix.data('last-position') - 1, $trix.data('last-position')])
            $trix[0].editor.deleteInDirection('forward')
            $trix[0].editor.insertAttachment attachment
            mentionsDivForTrix($trix).hide()
          onBlur: ->
            mentionsDivForTrix($trix).hide()
            @.disable()
            mentionsSelectizeForTrix($trix).css('left', -1000)
            $trix.focus()
            if @.items.length == 0
              $trix[0].editor.setSelectedRange([$trix.data('last-position') - 1, $trix.data('last-position')])
              $trix[0].editor.deleteInDirection('forward')
          onDropdownClose: ->
            mentionsDivForTrix($trix).hide()
          onDropdownOpen: ($dropdown) ->
            rect = $trix[0].editor.getClientRectAtPosition($trix[0].editor.getPosition())
            if rect != undefined
              $dropdown.css('top', 34)
              if rect.left + 200 > $trix.offset().left + $trix.width()
                $dropdown.css('left', $trix.offset().left + $trix.width() - (rect.left + 210))
          onType: (str) ->
            rect = $trix[0].editor.getClientRectAtPosition($trix[0].editor.getPosition())
            if rect.left + 200 > $trix.offset().left + $trix.width()
              mentionsSelectizeDropdownForTrix($trix).css('left', $trix.offset().left + $trix.width() - (rect.left + 210))

    openMentionsSelectize = ($trix, editor) ->
      $trix.data 'last-position', editor.getPosition()

      mentionsInput = mentionsInputForTrix($trix)
      mentionsSelectize = mentionsSelectizeForTrix($trix)
      rect = editor.getClientRectAtPosition(editor.getPosition())

      mentionsSelectize.css('left', rect.left - 10)
      mentionsSelectize.css('top', rect.top - 4)
      mentionsInput[0].selectize.clear()
      mentionsInput[0].selectize.enable()
      mentionsDivForTrix($trix).show()
      mentionsInput[0].selectize.focus()

    if $trix.data(MENTIONS_PATH).length > 0
      createMentionsDivForTrix($trix)
      initializeMentionsSelectize($trix)
      $trix.on 'trix-change', ->
        editor = @.editor
        char = editor.getDocument().toString().charAt(editor.getPosition() - 1)
        openMentionsSelectize($(@), editor) if char == '@'

trix_mentions.scss

[data-trix-attachment] {
  display: inline-block;
}
span.trix-mention + figcaption {
  display: none;
}

trix-mentions {
  .selectize-control {
    position: fixed
  }
  .selectize-input {
    border: none !important;
    background: none !important;
    box-shadow: none !important;
  }
  .selectize-control, .selectize-dropdown {
    width: 200px !important;
    z-index: 9999;
  }
}

@mitar, the autocomplete trigger is extremely primitive -- any time you hit "@", it's going to open the selectize control:

$trix.on 'trix-change', ->
  editor = @.editor
  char = editor.getDocument().toString().charAt(editor.getPosition() - 1)
  openMentionsSelectize($(@), editor) if char == '@'

I expect you can expand the if char == '@' conditional to do a better evaluation of context and decide if you want to call openMentionsSelectize.

I've spent the last couple hours trying to debug an error I'm getting and my JS skills just aren't there, especially with coffee thrown into the mix. Hopefully this will be an easy error on my part that you can direct me on how to resolve.

Line 82 of trix_mentions.js.coffee is what's triggering the error.
if $trix.data(MENTIONS_PATH).length > 0

Error as seen in Firefox:
TypeError: $trix.data(...) is undefined

Error as seen in Chrome:

Uncaught TypeError: Cannot read property 'length' of undefined
    at Function.Utility.TrixMentions.TrixMentions.prepare (trix_mentions.self-857d9c9….js?body=1:105)
    at mentionable_trix.self-9ca102d….js?body=1:4
    at triggerEvent (trix.self-34b57b1….js?body=1:16)
    at HTMLElement.notify (trix.self-34b57b1….js?body=1:21)
    at trix.self-34b57b1….js?body=1:21
Utility.TrixMentions.TrixMentions.prepare @ trix_mentions.self-857d9c9….js?body=1:105
(anonymous) @ mentionable_trix.self-9ca102d….js?body=1:4
triggerEvent @ trix.self-34b57b1….js?body=1:16
notify @ trix.self-34b57b1….js?body=1:21
(anonymous) @ trix.self-34b57b1….js?body=1:21

I wasn't sure how I was supposed to set this up. I think all I need to configure is the path to my mentions, which I've done. Here is my config block:

  MENTIONS_PATH = "/user/mentions?r"
  MENTIONS_DIV_ID = "#trix-mentions-"
  MENTIONS_INPUT_ID = MENTIONS_DIV_ID + "input-"

@lawso017, Any thoughts on how I should proceed? I'm running selectize.js 0.12.4 which appears to be the latest. Rails 5.1.2 on Ruby 2.4.1. Thanks!

@blimey85, the MENTIONS_PATH constant shouldn't need to be changed in your implementation. It's just defined as a constant to prevent typos in the code... we use the defined value "mentions-path" to identify the data attribute containing the path in the control.

In your case, you just need to ensure that your trix element has the data attribute:

data-mentions-path="/user/mentions?r"

defined.