[Timeline]: Earliest date defaulted to current date when found date was later than current day

@navikt/core/react/src/timeline/hooks/useTimelineRows.ts

@@ -134,17 +134,33 @@ export const useTimelineRows = (
     [rows, startDate, endDate, direction],
   );
 
-const earliestDate = (earliest: Date, period: Period) =>
-  period.start < earliest ? period.start : earliest;
+export const useEarliestDate = ({
+  startDate,
+  rows,
+}: {
+  startDate?: Date;
+  rows: Omit<Period, "id" | "endInclusive">[][];
+}) =>
+  useMemo(() => {
+    if (startDate) {
+      return startDate;
+    }
 
-const earliestFomDate = (rader: Period[][]) =>
-  rader.flat().reduce(earliestDate, new Date());
+    const startDates = rows
+      .flat()
+      .filter((period) => period.start)
+      .map((period) => period.start);
 
-export const useEarliestDate = ({ startDate, rows }: any) =>
-  useMemo(
-    () => (startDate ? startDate : earliestFomDate(rows)),
-    [startDate, rows],
-  );
+    if (startDates.length === 0) {
+      return new Date();
+    }
+
+    const earliestDate = startDates.reduce((earliest, current) =>
+      current < earliest ? current : earliest,
+    );
+
+    return earliestDate;
+  }, [startDate, rows]);
 
 const latestDate = (latest: Date, period: Period) =>
   period.end > latest ? period.end : latest;

@navikt/core/react/src/timeline/tests/useTimelineRows.test.ts

@@ -0,0 +1,133 @@
+import { renderHook } from "@testing-library/react";
+import { addDays, isSameDay } from "date-fns";
+import { describe, expect, test } from "vitest";
+import {
+  useEarliestDate,
+  useLatestDate,
+  useTimelineRows,
+} from "../hooks/useTimelineRows";
+
+describe("useEarliestDate", () => {
+  test("returns the provided startDate if it exists", () => {
+    const startDate = new Date(2023, 0, 1);
+    const { result } = renderHook(() =>
+      useEarliestDate({ startDate, rows: [] }),
+    );
+    expect(result.current).toEqual(startDate);
+  });
+
+  test("returns the earliest date from the rows if startDate is not provided", () => {
+    const rows = [
+      [{ start: new Date(2023, 0, 1) }],
+      [{ start: new Date(2022, 0, 1) }],
+    ];
+
+    /* @ts-expect-error asdas */
+    const { result } = renderHook(() => useEarliestDate({ rows }));
+    expect(result.current).toEqual(new Date(2022, 0, 1));
+  });
+
+  test("returns the earliest date from the rows if startDate is not provided and date is later than todays date", () => {
+    const earliestDate = addDays(new Date(), 400);
+    const rows = [
+      [{ start: earliestDate }],
+      [{ start: addDays(earliestDate, 40) }],
+    ];
+
+    /* @ts-expect-error asdas */
+    const { result } = renderHook(() => useEarliestDate({ rows }));
+    expect(result.current).toEqual(earliestDate);
+  });
+
+  test("returns the current date if no startDate and rows are empty", () => {
+    const { result } = renderHook(() => useEarliestDate({ rows: [] }));
+    expect(isSameDay(result.current, new Date())).toBeTruthy();
+  });
+});
+
+describe("useLatestDate", () => {
+  test("returns the provided endDate if it exists", () => {
+    const endDate = new Date(2023, 0, 1);
+    const { result } = renderHook(() => useLatestDate({ endDate, rows: [] }));
+    expect(result.current).toEqual(endDate);
+  });
+
+  test("returns the latest date from the rows plus one day if endDate is not provided", () => {
+    const rows = [
+      [{ start: new Date(2023, 0, 1), end: new Date(2023, 0, 10) }],
+      [{ start: new Date(2022, 0, 1), end: new Date(2022, 0, 5) }],
+    ];
+    const { result } = renderHook(() => useLatestDate({ rows }));
+    expect(result.current).toEqual(addDays(new Date(2023, 0, 10), 1));
+  });
+
+  test("returns the current date plus one day if no endDate and rows are empty", () => {
+    const { result } = renderHook(() => useLatestDate({ rows: [] }));
+    expect(result.current).toEqual(addDays(new Date(0), 1));
+  });
+});
+
+describe("useTimelineRows", () => {
+  const rows = [
+    {
+      label: "Row 1",
+      periods: [
+        {
+          start: new Date(2023, 0, 1),
+          end: new Date(2023, 0, 10),
+          status: "active",
+        },
+        {
+          start: new Date(2023, 0, 15),
+          end: new Date(2023, 0, 20),
+          status: "inactive",
+        },
+      ],
+    },
+    {
+      label: "Row 2",
+      periods: [
+        {
+          start: new Date(2022, 0, 1),
+          end: new Date(2022, 0, 5),
+          status: "active",
+        },
+      ],
+    },
+  ];
+
+  test("returns the correct timeline rows", () => {
+    const startDate = new Date(2022, 0, 1);
+    const endDate = new Date(2023, 0, 31);
+    const direction = "left";
+    const { result } = renderHook(() =>
+      useTimelineRows(rows, startDate, endDate, direction),
+    );
+
+    expect(result.current).toHaveLength(2);
+    expect(result.current[0].periods).toHaveLength(2);
+    expect(result.current[1].periods).toHaveLength(1);
+  });
+
+  test("handles empty rows", () => {
+    const startDate = new Date(2022, 0, 1);
+    const endDate = new Date(2023, 0, 31);
+    const direction = "left";
+    const { result } = renderHook(() =>
+      useTimelineRows([], startDate, endDate, direction),
+    );
+
+    expect(result.current).toHaveLength(0);
+  });
+
+  test("handles different directions", () => {
+    const startDate = new Date(2022, 0, 1);
+    const endDate = new Date(2023, 0, 31);
+    const direction = "right";
+    const { result } = renderHook(() =>
+      useTimelineRows(rows, startDate, endDate, direction),
+    );
+
+    expect(result.current[0].periods[0].start).toEqual(new Date(2023, 0, 15));
+  });
+});