1 files changed, 49 insertions, 0 deletions
diff --git a/app/assets/javascripts/frequent_items/utils.js b/app/assets/javascripts/frequent_items/utils.js
new file mode 100644
index 00000000000..aba692e4b99
--- /dev/null
+++ b/app/assets/javascripts/frequent_items/utils.js
@@ -0,0 +1,49 @@
+import _ from 'underscore';
+import bp from '~/breakpoints';
+import { FREQUENT_ITEMS, HOUR_IN_MS } from './constants';
+
+export const isMobile = () => {
+  const screenSize = bp.getBreakpointSize();
+
+  return screenSize === 'sm' || screenSize === 'xs';
+};
+
+export const getTopFrequentItems = items => {
+  if (!items) {
+    return [];
+  }
+  const frequentItemsCount = isMobile()
+    ? FREQUENT_ITEMS.LIST_COUNT_MOBILE
+    : FREQUENT_ITEMS.LIST_COUNT_DESKTOP;
+
+  const frequentItems = items.filter(item => item.frequency >= FREQUENT_ITEMS.ELIGIBLE_FREQUENCY);
+
+  if (!frequentItems || frequentItems.length === 0) {
+    return [];
+  }
+
+  frequentItems.sort((itemA, itemB) => {
+    // Sort all frequent items in decending order of frequency
+    // and then by lastAccessedOn with recent most first
+    if (itemA.frequency !== itemB.frequency) {
+      return itemB.frequency - itemA.frequency;
+    } else if (itemA.lastAccessedOn !== itemB.lastAccessedOn) {
+      return itemB.lastAccessedOn - itemA.lastAccessedOn;
+    }
+
+    return 0;
+  });
+
+  return _.first(frequentItems, frequentItemsCount);
+};
+
+export const updateExistingFrequentItem = (frequentItem, item) => {
+  const accessedOverHourAgo =
+    Math.abs(item.lastAccessedOn - frequentItem.lastAccessedOn) / HOUR_IN_MS > 1;
+
+  return {
+    ...item,
+    frequency: accessedOverHourAgo ? frequentItem.frequency + 1 : frequentItem.frequency,
+    lastAccessedOn: accessedOverHourAgo ? Date.now() : frequentItem.lastAccessedOn,
+  };
+};