fix(core): using correct timezone when parsing dates

src/app/core/entity/schema-datatypes/datatype-date-only.spec.ts

@@ -2,9 +2,23 @@ import { dateOnlyEntitySchemaDatatype } from "./datatype-date-only";
 
 describe("Schema data type:Date", () => {
   it("should not fail on null values", () => {
-    const nullDateRes = dateOnlyEntitySchemaDatatype.transformToDatabaseFormat(
-      null
-    );
+    const nullDateRes =
+      dateOnlyEntitySchemaDatatype.transformToDatabaseFormat(null);
     expect(nullDateRes).toBeUndefined();
   });
+
+  it("should correctly transform values", () => {
+    const date = new Date(2022, 0, 1);
+
+    const dbFormat =
+      dateOnlyEntitySchemaDatatype.transformToDatabaseFormat(date);
+    expect(dbFormat).toBe("2022-01-01");
+
+    const objFormat: Date =
+      dateOnlyEntitySchemaDatatype.transformToObjectFormat(dbFormat);
+    expect(objFormat).toBeInstanceOf(Date);
+    expect(objFormat.getFullYear()).toBe(2022);
+    expect(objFormat.getMonth()).toBe(0);
+    expect(objFormat.getDate()).toBe(1);
+  });
 });

src/app/core/entity/schema-datatypes/datatype-date-only.ts

@@ -44,8 +44,11 @@ export const dateOnlyEntitySchemaDatatype: EntitySchemaDatatype = {
     );
   },
 
-  transformToObjectFormat: (value) => {
-    const date = new Date(value);
+  transformToObjectFormat: (value: string) => {
+    // new Date("2022-01-01") is interpreted as UTC time whereas new Date(2022, 0, 1) is local time
+    // -> we want local time to represent the same day wherever used.
+    const values = value.split("-").map((v) => Number(v));
+    const date = new Date(values[0], values[1] - 1, values[2]);
     if (Number.isNaN(date.getTime())) {
       throw new Error("failed to convert data to Date object: " + value);
     }

src/app/core/entity/schema-datatypes/datatype-month.ts

@@ -40,12 +40,14 @@ export const monthEntitySchemaDatatype: EntitySchemaDatatype = {
     );
   },
 
-  transformToObjectFormat: (value) => {
-    value = value
+  transformToObjectFormat: (value: string) => {
+    const values = value
       .toString()
       .replace(/-(\d)-/g, "-0$1-")
-      .replace(/-(\d)$/g, "-0$1");
-    const date = new Date(value);
+      .replace(/-(\d)$/g, "-0$1")
+      .split("-")
+      .map((v) => Number(v));
+    const date = new Date(values[0], values[1] - 1);
     if (Number.isNaN(date.getTime())) {
       throw new Error("failed to convert data to Date object: " + value);
     }