Add constants for presets

ee/app/assets/javascripts/roadmap/constants.js

+import { s__ } from '~/locale';
+
 export const TIMEFRAME_LENGTH = 6;
 
 export const EPIC_DETAILS_CELL_WIDTH = 320;
@@ -13,3 +15,27 @@ export const SCROLL_BAR_SIZE = 15;
 export const TIMELINE_END_OFFSET_HALF = 8;
 
 export const TIMELINE_END_OFFSET_FULL = 16;
+
+export const PRESET_TYPES = {
+  QUARTERS: 'QUARTERS',
+  MONTHS: 'MONTHS',
+  WEEKS: 'WEEKS',
+};
+
+export const PRESET_DEFAULTS = {
+  QUARTERS: {
+    TIMEFRAME_LENGTH: 18,
+    emptyStateDefault: s__('GroupRoadmap|To view the roadmap, add a planned start or finish date to one of your epics in this group or its subgroups. In the quarters view, only epics in the past quarter, current quarter, and next 4 quarters are shown – from %{startDate} to %{endDate}.'),
+    emptyStateWithFilters: s__('GroupRoadmap|To widen your search, change or remove filters. In the quarters view, only epics in the past quarter, current quarter, and next 4 quarters are shown – from %{startDate} to %{endDate}.'),
+  },
+  MONTHS: {
+    TIMEFRAME_LENGTH: 7,
+    emptyStateDefault: s__('GroupRoadmap|To view the roadmap, add a planned start or finish date to one of your epics in this group or its subgroups. In the months view, only epics in the past month, current month, and next 5 months are shown – from %{startDate} to %{endDate}.'),
+    emptyStateWithFilters: s__('GroupRoadmap|To widen your search, change or remove filters. In the months view, only epics in the past month, current month, and next 5 months are shown – from %{startDate} to %{endDate}.'),
+  },
+  WEEKS: {
+    TIMEFRAME_LENGTH: 42,
+    emptyStateDefault: s__('GroupRoadmap|To view the roadmap, add a planned start or finish date to one of your epics in this group or its subgroups. In the weeks view, only epics in the past week, current week, and next 4 weeks are shown – from %{startDate} to %{endDate}.'),
+    emptyStateWithFilters: s__('GroupRoadmap|To widen your search, change or remove filters. In the weeks view, only epics in the past week, current week, and next 4 weeks are shown – from %{startDate} to %{endDate}.'),
+  },
+};