Fix conversion of dates from C# to V8

We need to use the date constructor to create a date, otherwise the
order of invocation of the set methods influences the result leading to
incorrect date values. There is no permutation which is always correct.

Example: 1967-04-01 00:00:00
Depending on the timezone the milliseconds from C# could represent
1967-03-31 23:00:00. If we now set the month to April we get the
31st of April which JavaScript interprets as the 1st of May.

Even if we don't use the current date as starting point but
1970-01-01 00:00:00 using the set methods can lead to errors.

Example: 1972-02-29 00:00:00
Since we start from 1970-01-01 00:00:00 (UTC) which was not a leap year,
we need to set the year first. Otherwise, if we now set the month to
February and the date to 29 we get the 1st of March.

Another case is can occur when changing daylight savings time.

Author: spahnke

Source/Noesis.Javascript/JavascriptInterop.cpp

@@ -387,13 +387,6 @@ double GetDateComponent(Isolate* isolate, Handle<Date> date, const char* compone
     return componentValue->NumberValue(isolate->GetCurrentContext()).ToChecked();
 }
 
-void SetDateComponent(Isolate* isolate, Handle<Date> date, const char* component, double value)
-{
-    auto getComponent = date->Get(isolate->GetCurrentContext(), String::NewFromUtf8(isolate, component)).ToLocalChecked().As<Function>();
-    Handle<Value> parameters[] = { JavascriptInterop::ConvertToV8(value) };
-    getComponent->Call(date, 1, parameters);
-}
-
 System::DateTime^ JavascriptInterop::ConvertDateFromV8(Handle<Date> date)
 {
     auto isolate = JavascriptContext::GetCurrentIsolate();
@@ -412,18 +405,22 @@ Handle<Date> JavascriptInterop::ConvertDateTimeToV8(System::DateTime^ dateTime)
     auto isolate = JavascriptContext::GetCurrentIsolate();
     EscapableHandleScope handleScope(isolate);
 
-    auto date = v8::Date::New(isolate->GetCurrentContext(), SystemInterop::ConvertFromSystemDateTime(dateTime)).ToLocalChecked().As<Date>();
     if (dateTime->Kind == System::DateTimeKind::Utc)
-        return handleScope.Escape(date);
-
-    SetDateComponent(isolate, date, "setFullYear", dateTime->Year);
-    SetDateComponent(isolate, date, "setMonth", dateTime->Month - 1);
-    SetDateComponent(isolate, date, "setDate", dateTime->Day);
-    SetDateComponent(isolate, date, "setHours", dateTime->Hour);
-    SetDateComponent(isolate, date, "setMinutes", dateTime->Minute);
-    SetDateComponent(isolate, date, "setSeconds", dateTime->Second);
-    SetDateComponent(isolate, date, "setMilliseconds", dateTime->Millisecond);
-    return handleScope.Escape(date);
+        return handleScope.Escape(v8::Date::New(isolate->GetCurrentContext(), SystemInterop::ConvertFromSystemDateTime(dateTime)).ToLocalChecked().As<Date>());
+
+    auto year = JavascriptInterop::ConvertToV8(dateTime->Year);
+    auto month = JavascriptInterop::ConvertToV8(dateTime->Month - 1);
+    auto day = JavascriptInterop::ConvertToV8(dateTime->Day);
+    auto hour = JavascriptInterop::ConvertToV8(dateTime->Hour);
+    auto minute = JavascriptInterop::ConvertToV8(dateTime->Minute);
+    auto second = JavascriptInterop::ConvertToV8(dateTime->Second);
+    auto millisecond = JavascriptInterop::ConvertToV8(dateTime->Millisecond);
+
+    auto globalObj = isolate->GetCurrentContext()->Global();
+    auto dateConstructor = Local<Function>::Cast(globalObj->Get(String::NewFromUtf8(isolate, "Date")));
+    Handle<Value> parameters[] = { year, month, day, hour, minute, second, millisecond };
+
+    return handleScope.Escape(dateConstructor->NewInstance(isolate->GetCurrentContext(), 7, parameters).ToLocalChecked().As<Date>());
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////

Tests/Noesis.Javascript.Tests/DateTest.cs

@@ -1,6 +1,8 @@
 using System;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using FluentAssertions;
+using System.Collections.Generic;
+using System.Linq;
 
 namespace Noesis.Javascript.Tests
 {
@@ -115,8 +117,7 @@ public void SetDateTimeLocal_DateWhereTimezoneDatabaseIsImportant()
             _context.Run("val.getSeconds()").Should().BeOfType<int>().Which.Should().Be(0);
         }
 
-        [TestMethod]
-        [Ignore]
+        //[TestMethod]
         public void SetAndReadDateTimeUtc_DateWhereTimezoneDatabaseIsImportant()
         {
             var dateTime = new DateTime(1978, 6, 15, 0, 0, 0, DateTimeKind.Utc);
@@ -126,6 +127,26 @@ public void SetAndReadDateTimeUtc_DateWhereTimezoneDatabaseIsImportant()
             dateFromV8.ToUniversalTime().Should().Be(dateTime); // this cannot work without an external dependency like NodaTime
         }
 
+        //[TestMethod]
+        public void SetAndReadDateTimeUtc_EdgeCaseOfAMonthWith30Days()
+        {
+            var dateTime = new DateTime(1967, 4, 1, 0, 0, 0, DateTimeKind.Utc);
+            _context.SetParameter("val", dateTime);
+
+            var dateFromV8 = (DateTime) _context.Run("val");
+            dateFromV8.ToUniversalTime().Should().Be(dateTime); // this cannot work without an external dependency like NodaTime
+        }
+
+        //[TestMethod]
+        public void SetAndReadDateTimeUtc_LeapYear()
+        {
+            var dateTime = new DateTime(1972, 2, 29, 0, 0, 0, DateTimeKind.Utc);
+            _context.SetParameter("val", dateTime);
+
+            var dateFromV8 = (DateTime) _context.Run("val");
+            dateFromV8.ToUniversalTime().Should().Be(dateTime); // this cannot work without an external dependency like NodaTime
+        }
+
         [TestMethod]
         public void SetAndReadDateTimeLocal_DateWhereTimezoneDatabaseIsImportant()
         {
@@ -135,6 +156,24 @@ public void SetAndReadDateTimeLocal_DateWhereTimezoneDatabaseIsImportant()
             _context.Run("val").Should().Be(dateTime);
         }
 
+        [TestMethod]
+        public void SetAndReadDateTimeLocal_EdgeCaseOfAMonthWith30Days()
+        {
+            var dateTime = new DateTime(1967, 4, 1, 0, 0, 0, DateTimeKind.Local);
+            _context.SetParameter("val", dateTime);
+
+            _context.Run("val").Should().Be(dateTime);
+        }
+
+        [TestMethod]
+        public void SetAndReadDateTimeLocal_LeapYear()
+        {
+            var dateTime = new DateTime(1972, 2, 29, 0, 0, 0, DateTimeKind.Local);
+            _context.SetParameter("val", dateTime);
+
+            _context.Run("val").Should().Be(dateTime);
+        }
+
         [TestMethod]
         public void SetAndReadDateTimeUnspecified_DateWhereTimezoneDatabaseIsImportant()
         {
@@ -144,11 +183,51 @@ public void SetAndReadDateTimeUnspecified_DateWhereTimezoneDatabaseIsImportant()
             _context.Run("val").Should().Be(dateTime);
         }
 
+        [TestMethod]
+        public void SetAndReadDateTimeUnspecified_EdgeCaseOfAMonthWith30Days()
+        {
+            var dateTime = new DateTime(1967, 4, 1);
+            _context.SetParameter("val", dateTime);
+
+            _context.Run("val").Should().Be(dateTime);
+        }
+
+        [TestMethod]
+        public void SetAndReadDateTimeUnspecified_LeapYear()
+        {
+            var dateTime = new DateTime(1972, 2, 29);
+            _context.SetParameter("val", dateTime);
+
+            _context.Run("val").Should().Be(dateTime);
+        }
+
         [TestMethod]
         public void CreateFixedDateInJavaScript_DateWhereTimezoneDatabaseIsImportant()
         {
             DateTime dateAsReportedByV8 = (DateTime) _context.Run("new Date(1978, 5, 15)");
             dateAsReportedByV8.Should().Be(new DateTime(1978, 6, 15));
         }
+
+        [TestMethod]
+        public void SetAndReadDateTimeLocal_DateRange()
+        {
+            var startDate = new DateTime(1900, 1, 1, 0, 0, 0, DateTimeKind.Local);
+            var endDate = new DateTime(2100, 1, 1, 0, 0, 0, DateTimeKind.Local);
+            var totalDays = (endDate - startDate).TotalDays;
+
+            var errorDates = new List<string>();
+
+            for (var i = 0; i < totalDays; i++)
+            {
+                var date = startDate.AddDays(i);
+                _context.SetParameter("val", date);
+                var result = (DateTime) _context.Run("val");
+                if (result != date)
+                    errorDates.Add($"Expected {date}, but got {result}");
+            }
+
+            if (errorDates.Any())
+                Assert.Fail(string.Join("\n", errorDates));
+        }
     }
 }