From d3579715544aae3550715581c11526e283a11ec7 Mon Sep 17 00:00:00 2001
From: Joe Fleming <joe.fleming@gmail.com>
Date: Fri, 22 Apr 2016 11:25:06 -0700
Subject: [PATCH] add date interval module

---
 package.json                  |  1 +
 src/helpers/index_interval.js | 37 +++++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)
 create mode 100644 src/helpers/index_interval.js

diff --git a/package.json b/package.json
index ad11b3b..e4c2e45 100644
--- a/package.json
+++ b/package.json
@@ -32,6 +32,7 @@
   "dependencies": {
     "elasticsearch": "~11.0.1",
     "lodash": "~4.11.1",
+    "moment": "~2.10.6",
     "puid": "~1.0.5"
   }
 }
diff --git a/src/helpers/index_interval.js b/src/helpers/index_interval.js
new file mode 100644
index 0000000..555f96d
--- /dev/null
+++ b/src/helpers/index_interval.js
@@ -0,0 +1,37 @@
+import moment from 'moment';
+
+export const intervals = [
+  'y',
+  'M',
+  'w',
+  'd',
+  'h',
+  'm'
+];
+
+export const intervalNames = [
+  'year',
+  'month',
+  'week',
+  'day',
+  'hour',
+  'minute'
+];
+
+export default function getTimestamp(intervalStr) {
+  const index = intervals.indexOf(intervalStr);
+  if (index === -1) throw new Error('Invalid index interval: ', intervalStr);
+
+  const startType = intervalNames[intervalStr];
+  const m = moment();
+  m.startOf(startType);
+
+  let dateString = 'YYYY-MM-DD';
+  if (startType === 'hour') {
+    dateString += '-HH';
+  }
+  if (startType === 'minute') {
+    dateString += '-HH-mm';
+  }
+  return m.format(dateString);
+}
\ No newline at end of file