AJAX error when adding JSON Feed display

Problem/Motivation

Browser AJAX error when attempting to add a JSON Feed display.

Steps to reproduce

Add new view of type Content, add JSON Feed display. When saving the view or attempting to edit field settings the following error messages appear:

• Row style plugin requires specifying which views fields to use for JSON feed item.
• Either content_html or content_text must have a value.
• Oops, something went wrong. Check your browser's developer console for more details.

The console shows the following error:

[Error] AjaxError: 
An AJAX HTTP error occurred.
HTTP Result Code: 200
Debugging information follows.
Path: /admin/structure/views/ajax/display/publications_json/json_feed_1/row_options
StatusText: parsererror
ResponseText: 
Warning:  Undefined array key "id_field" in /app/docroot/modules/contrib/json_feed/src/Plugin/views/row/JsonFeedFields.php on line 54
Warning:  Undefined array key "url_field" in /app/docroot/modules/contrib/json_feed/src/Plugin/views/row/JsonFeedFields.php on line 63
Warning:  Undefined array key "external_url_field" in /app/docroot/modules/contrib/json_feed/src/Plugin/views/row/JsonFeedFields.php on line 72
Warning:  Undefined array key "title_field" in /app/docroot/modules/contrib/json_feed/src/Plugin/views/row/JsonFeedFields.php on line 80
Warning:  Undefined array key "content_html_field" in /app/docroot/modules/contrib/json_feed/src/Plugin/views/row/JsonFeedFields.php on line 88
Warning:  Undefined array key "content_text_field" in /app/docroot/modules/contrib/json_feed/src/Plugin/views/row/JsonFeedFields.php on line 96
Warning:  Undefined array key "summary_field" in /app/docroot/modules/contrib/json_feed/src/Plugin/views/row/JsonFeedFields.php on line 104
Warning:  Undefined array key "image_field" in /app/docroot/modules/contrib/json_feed/src/Plugin/views/row/JsonFeedFields.php on line 112
Warning:  Undefined array key "banner_image_field" in /app/docroot/modules/contrib/json_feed/src/Plugin/views/row/JsonFeedFields.php on line 120
Warning:  Undefined array key "date_published_field" in /app/docroot/modules/contrib/json_feed/src/Plugin/views/row/JsonFeedFields.php on line 128
Warning:  Undefined array key "date_modified_field" in /app/docroot/modules/contrib/json_feed/src/Plugin/views/row/JsonFeedFields.php on line 136
Warning:  Undefined array key "tags_field" in /app/docroot/modules/contrib/json_feed/src/Plugin/views/row/JsonFeedFields.php on line 144
Warning:  Undefined array key "author_name_field" in /app/docroot/modules/contrib/json_feed/src/Plugin/views/row/JsonFeedFields.php on line 159
Warning:  Undefined array key "author_url_field" in /app/docroot/modules/contrib/json_feed/src/Plugin/views/row/JsonFeedFields.php on line 168
Warning:  Undefined array key "author_avatar_field" in /app/docroot/modules/contrib/json_feed/src/Plugin/views/row/JsonFeedFields.php on line 177
... 

(Full error message is in attached file.)