diff --git a/packages/core/api/database.js b/packages/core/api/database.js
index 739b2b620..551c3f75d 100644
--- a/packages/core/api/database.js
+++ b/packages/core/api/database.js
@@ -2,12 +2,14 @@ import Storage from "../helpers/storage";
 import fuzzysearch from "fuzzysearch";
 var tfun = require("transfun/transfun.js").tfun;
 tfun = global.tfun;
-import { extractValues } from "../utils";
+import { extractValues, groupBy } from "../utils";
+import { getWeekGroupFromTimestamp, months } from "../utils/date";
 
 const KEYS = {
   notes: "notes",
   notebooks: "notebooks"
 };
+
 function checkInitialized() {
   if (!this.isInitialized) {
     throw new Error(
@@ -15,13 +17,7 @@ function checkInitialized() {
     );
   }
 }
-function groupBy(xs, key) {
-  return tfun.reduce(function(rv, x) {
-    var v = key instanceof Function ? key(x) : x[key];
-    (rv[v] = rv[v] || []).push(x);
-    return rv;
-  })(xs);
-}
+
 class Database {
   constructor(storage) {
     this.storage = new Storage(storage);
@@ -53,12 +49,39 @@ class Database {
     return extractValues(this.notes).reverse();
   }
 
-  //TODO
-  groupNotes() {
-    var c = groupBy(this.getNotes(), x =>
-      new Date(x.dateCreated).getFullYear()
-    );
-    return c;
+  /**
+   * Group notes by given criteria
+   * @param {string} by One from 'abc', 'month', 'year' or 'week'. Leave it empty for default grouping.
+   */
+  groupNotes(by) {
+    switch (by) {
+      case "abc":
+        return groupBy(notes, note => note.title[0].toUpperCase());
+      case "month":
+        return groupBy(
+          notes,
+          note => months[new Date(note.dateCreated).getMonth()]
+        );
+      case "week":
+        groupBy(notes, note => getWeekGroupFromTimestamp(note.dateCreated));
+      case "year":
+        groupBy(
+          notes,
+          note => months[new Date(note.dateCreated).getFullYear()]
+        );
+      default:
+        let timestamps = {
+          recent: getLastWeekTimestamp(7),
+          lastWeek: getLastWeekTimestamp(7) - 604800000 //seven day timestamp value
+        };
+        groupBy(notes, note =>
+          note.dateCreated >= timestamps.recent
+            ? "Recent"
+            : note.dateCreated >= timestamps.lastWeek
+            ? "Last week"
+            : "Older"
+        );
+    }
   }
 
   /**
diff --git a/packages/core/utils/date.js b/packages/core/utils/date.js
new file mode 100644
index 000000000..377a5e31d
--- /dev/null
+++ b/packages/core/utils/date.js
@@ -0,0 +1,69 @@
+function getWeeksInMonth(month, year) {
+  var weeks = [],
+    firstDate = new Date(year, month, 1),
+    lastDate = new Date(year, month + 1, 0),
+    numDays = lastDate.getDate();
+
+  var start = 1;
+  var end = 7 - firstDate.getDay();
+  while (start <= numDays) {
+    weeks.push({
+      start: new Date(year, month, start),
+      end: new Date(year, month, end)
+    });
+    start = end + 1;
+    end = end + 7;
+    if (end > numDays) end = numDays;
+  }
+  return weeks;
+}
+
+function getWeeksInYear(year) {
+  let weeks = [];
+  for (let i = 0; i <= 11; i++) {
+    weeks.concat(...getWeeksInMonth(i, year));
+  }
+  return weeks;
+}
+
+function getDayTimestamp(last) {
+  to = new Date().getDate() - last;
+  date = new Date();
+  return date.setDate(to);
+}
+
+function getLastWeekTimestamp() {
+  const t = new Date().getDate() + (6 - new Date().getDay() - 1) - 6;
+  const lastSaturday = new Date();
+  return lastSaturday.setDate(t);
+}
+export const months = [
+  "January",
+  "February",
+  "March",
+  "April",
+  "May",
+  "June",
+  "July",
+  "August",
+  "September",
+  "October",
+  "November",
+  "December"
+];
+let years = {};
+export function getWeekGroupFromTimestamp(timestamp) {
+  let date = new Date(timestamp);
+
+  if (!years.hasOwnProperty(date.getFullYear())) {
+    years[date.getFullYear()] = weeks;
+  }
+  let weeks = years[date.getFullYear()];
+
+  let week = weeks.find(v => date >= v.start && date <= v.end);
+
+  //Format: {month} {start} - {end}, {year}
+  return `${months[date.getMonth()]} ${week.start} - ${
+    week.end
+  }, ${date.getFullYear()}`;
+}
diff --git a/packages/core/utils/index.js b/packages/core/utils/index.js
index 4ce3bbb58..92169ac50 100644
--- a/packages/core/utils/index.js
+++ b/packages/core/utils/index.js
@@ -5,3 +5,11 @@ export function extractValues(obj) {
   }
   return t;
 }
+
+export function groupBy(xs, key) {
+  return tfun.reduce(function(rv, x) {
+    var v = key instanceof Function ? key(x) : x[key];
+    (rv[v] = rv[v] || []).push(x);
+    return rv;
+  })(xs);
+}