Fixing date to time conversion (#94)

* Fixing date to time conversion

* Update src/conversion.rs

Co-authored-by: Cory Grinstead <universalmind.candy@gmail.com>

---------

Co-authored-by: Darek <dchrostowski@medallia.com>
Co-authored-by: Cory Grinstead <universalmind.candy@gmail.com>

__tests__/dataframe.test.ts

@@ -1575,6 +1575,23 @@ describe("io", () => {
     const actual = df.toRecords();
     expect(actual).toEqual(expected);
   });
+  test("toRecords:date", () => {
+    const df = pl
+      .DataFrame({
+        date: [new Date()],
+      })
+      .withColumn(pl.col("date").cast(pl.Date).alias("date"));
+    const dt = new Date();
+    const expected = [
+      {
+        date: new Date(
+          Date.UTC(dt.getFullYear(), dt.getMonth(), dt.getDate(), 0, 0, 0, 0),
+        ),
+      },
+    ];
+    const actual = df.toRecords();
+    expect(JSON.stringify(actual)).toEqual(JSON.stringify(expected));
+  });
   test("toObject", () => {
     const expected = {
       foo: [1],

src/conversion.rs

@@ -127,8 +127,11 @@ impl<'a> ToNapiValue for Wrap<AnyValue<'a>> {
             AnyValue::Date(v) => {
                 let mut ptr = std::ptr::null_mut();
 
+                // Multiple days to get to Epoch time
+                let epoch_time: f64 = (v as f64) * 86400000.0;
+
                 check_status!(
-                    napi::sys::napi_create_date(env, v as f64, &mut ptr),
+                    napi::sys::napi_create_date(env, epoch_time, &mut ptr),
                     "Failed to convert rust type `AnyValue::Date` into napi value",
                 )?;