To make it possible to run Lens expressions on the Kibana server (for features like alerting), all expression functions have to be registered on the server as well as on the client. To do that, they have to be moved to a central common folder in the plugin folder, and imported and registered in the server side plugin as well as the current registration on the client side.

List of functions:

• lens_time_scale
• lens_counter_rate
• lens_rename_columns
• lens_format_column
• lens_datatable_column
• lens_datatable (relies on field formatter service)
• lens_metric_chart
• lens_pie
• lens_xy_legendConfig
• lens_xy_yConfig
• lens_xy_tickLabelsConfig
• lens_xy_gridlinesConfig
• lens_xy_axisTitlesVisibilityConfig
• lens_xy_layer
• lens_xy_chart

We also have to move the suffix formatter to the server because the datatable function depends on field formatters x-pack/plugins/lens/public/indexpattern_datasource/suffix_formatter.ts