Use non-US dates

static_src/components/app_activity/timestamp.jsx

@@ -2,7 +2,7 @@ import React from 'react';
 import PropTypes from 'prop-types';
 import moment from 'moment-timezone';
 
-const propTypes = { timestamp: PropTypes.string };
+const propTypes = { timestamp: PropTypes.string.isRequired };
 const formatTimestamp = timestamp =>
   moment(timestamp).tz(moment.tz.guess()).format('MMM DD YYYY HH:mm:ss z');
 

static_src/test/unit/util/format_date.spec.js

@@ -1,34 +1,31 @@
-
 import '../../global_setup.js';
 
 import formatDateTime from '../../../util/format_date';
 
-describe('format_date util', function () {
-  describe('when used with an invalid datetime', function () {
-    it('should throw an exception', function () {
-      function format () {
-        return formatDateTime('invaliddate');
-      }
-      expect(format).toThrow();
-    });
-  });
-
-  describe('when used with a valid datetime', function () {
-    describe('but without a timezone', function () {
-      it('should return a formatted datetime in UTC', function () {
-        const formatted = formatDateTime('2015-07-14T04:02:30Z');
-        const expected = '07/14/2015 04:02am UTC';
-        expect(formatted).toEqual(expected);
-      });
+describe('formatDateTime', () => {
+  for (const val of [null, undefined, '', 'invaliddate']) {
+    it(`should throw an exception when given an invalid value › ${val}`, () => {
+      expect(() => formatDateTime(val)).toThrow();
     });
+  }
 
-    describe('and with a valid timezone', function () {
-      it('should return a formatted datetime in that timezone', function () {
-        const tz = 'America/Los_Angeles';
-        const formatted = formatDateTime('2015-07-14T04:02:30Z', tz);
-        const expected = '07/13/2015 09:02pm PDT';
-        expect(formatted).toEqual(expected);
-      });
+  for (const { val, tz, output } of [
+    {
+      val: '2015-07-14T04:02:30Z',
+      output: 'Jul 14 2015 04:02am UTC'
+    },
+    {
+      val: '1988-10-01T18:58:30Z',
+      output: 'Oct 01 1988 06:58pm UTC'
+    },
+    {
+      val: '2015-07-14T04:02:30Z',
+      tz: 'America/Los_Angeles',
+      output: 'Jul 13 2015 09:02pm PDT'
+    }
+  ]) {
+    it(`should return a formatted datetime when given a valid value › ${val}`, () => {
+      expect(formatDateTime(val, tz)).toEqual(output);
     });
-  });
+  }
 });

static_src/util/format_date.js

@@ -1,18 +1,26 @@
 import moment from 'moment-timezone';
 
-const invalidMsg = 'Invalid datetimes cannot be formatted.';
+const makeInvalidDateTimeValueError = str =>
+  new Error(`could not format invalid date/time value: ${str}`);
 
 /**
- * Returns a formated datetime string
- * @params {String} datetime as a string
- * @params {String} timezone abbreviation - defaults to UTC
+ * formatDateTime returns a formatted date/time string.
  *
- * @returns {String} A "MM/DD/YYYY H:mma z" formatted string
- *                    i.e. 03/21/2016 10:39am PDT
+ * @params {String} date/time as a string
+ * @params {String} timezone abbreviation - defaults to "Etc/UTC"
+ *
+ * @returns {String} A "MMM DD YYYY hh:mma z" formatted string
+ *                   e.g. "Jul 13 2015 09:02pm PDT"
 */
-export default function formatDateTime(dateString, timezone = 'Etc/UTC') {
-  const d = moment(dateString);
+const formatDateTime = (str, timezone = 'Etc/UTC') => {
+  if (!str) {
+    throw makeInvalidDateTimeValueError(str);
+  }
+  const d = moment(str);
+  if (!d.isValid()) {
+    throw makeInvalidDateTimeValueError(str);
+  }
+  return d.tz(timezone).format('MMM DD YYYY hh:mma z');
+};
 
-  if (!d.isValid()) throw new Error(invalidMsg);
-  return d.tz(timezone).format('MM/DD/YYYY hh:mma z');
-}
+export default formatDateTime;