Fix some exceptional cases

index.js

@@ -18,7 +18,23 @@ module.exports.getJsDateFromExcel = (excelDate) => {
   const missingLeapYearDay = secondsInDay * 1000;
   const delta = excelDate - (25567 + 2);
   const parsed = delta * missingLeapYearDay;
-  const date = new Date(parsed)
+  const parsedDate = new Date(parsed);
+
+  const fractionalDay = excelDate - Math.floor(excelDate) + 0.0000001;
+  let totalSeconds = Math.floor(secondsInDay * fractionalDay);
+  const seconds = totalSeconds % 60;
+  totalSeconds -= seconds;
+  const hours = Math.floor(totalSeconds / (60 * 60));
+  const minutes = Math.floor(totalSeconds / 60) % 60;
+
+  const date = new Date(
+    parsedDate.getFullYear(),
+    parsedDate.getMonth(),
+    parsedDate.getDate(),
+    hours,
+    minutes,
+    seconds
+  );
 
   if (Object.prototype.toString.call(date) === "[object Date]" ) {
     if (isNaN(date.getTime())) {

package.json

@@ -33,6 +33,7 @@
   },
   "homepage": "https://github.com/oleg-koval/excel-date-to-js#readme",
   "devDependencies": {
+    "mockdate": "^3.0.2",
     "semantic-release": "^15.13.24",
     "semantic-release-npm-github-publish": "^1.1.10",
     "tape": "^4.8.0"

test/index.js

@@ -1,27 +1,63 @@
 const test = require('tape');
+const mockDate = require('mockdate');
+
 const { getJsDateFromExcel } = require('../index');
 
 test('should convert Excel date to JS date', function (t) {
+  mockDate.set('2020-05-19T22:00:00.000Z');
+
   const actual = getJsDateFromExcel(42510).toISOString();
-  const expected = new Date('2016-05-20T00:00:00.000Z').toISOString();
+  const expected = new Date('2016-05-19T22:00:00.000Z').toISOString();
+  t.equal(actual, expected);
+  t.end()
+
+  mockDate.reset();
+});
+
+test('should convert Excel date to JS date', function (t) {
+  mockDate.set('2020-05-19T22:00:00.000Z');
+
+  const actual = getJsDateFromExcel(43078.416666666664).toISOString();
+  const expected = new Date('2017-12-09T09:00:00.000Z').toISOString();
+  t.equal(actual, expected);
+  t.end()
+
+  mockDate.reset()
+});
+
+test('should convert Excel date to JS date (5/19/2013 21:29, from https://goo.gl/Ejbext)', function (t) {
+  mockDate.set('2020-05-19T22:00:00.000Z');
+
+  const actual = getJsDateFromExcel(41413.895150462966).toISOString();
+  const expected = new Date('2013-05-19T19:29:01.000Z').toISOString();
   t.equal(actual, expected);
   t.end()
+
+  mockDate.reset()
 });
 
 test('should convert return an error on wrong input', function (t) {
+  mockDate.set('2020-05-19T22:00:00.000Z');
+
   try {
-    const actual = getJsDateFromExcel('text');
+    getJsDateFromExcel('text');
   } catch ({ message }) {
     t.equal(message, 'wrong input format')
   }
   t.end()
+
+  mockDate.reset()
 });
 
 test('should convert return an error on wrong excel date', function (t) {
+  mockDate.set('2020-05-19T22:00:00.000Z');
+
   try {
-    const actual = getJsDateFromExcel(7312873827);
+    getJsDateFromExcel(7312873827);
   } catch ({ message }) {
     t.equal(message, 'wrong excel date input')
   }
   t.end()
+
+  mockDate.reset()
 });