fix(pagination): window totalItems for performance (#2160)

Fixes #2156

tests/Pagination/Pagination.test.svelte

@@ -11,6 +11,7 @@
   export let pageSizeInputDisabled = false;
   export let pageSize = 10;
   export let pageSizes: ReadonlyArray<number> = [10];
+  export let pageWindow: undefined | number = undefined;
   export let pagesUnknown = false;
 </script>
 
@@ -23,6 +24,7 @@
   {itemsPerPageText}
   {pageInputDisabled}
   {pageSizeInputDisabled}
+  {pageWindow}
   bind:pageSize
   {pageSizes}
   {pagesUnknown}

tests/Pagination/Pagination.test.ts

@@ -196,4 +196,22 @@ describe("Pagination", () => {
 
     expect(screen.getByText("0–0 of 0 items")).toBeInTheDocument();
   });
+
+  it("renders a cap of 1000 page numbers by default", () => {
+    render(Pagination, {
+      props: { totalItems: 100_000 },
+    });
+
+    const pageNumbers = screen.getByLabelText(/Page number, of 10000 pages/);
+    expect(pageNumbers).toHaveLength(1_000 + 1);
+  });
+
+  it("renders a custom page window", () => {
+    render(Pagination, {
+      props: { totalItems: 100_000, pageWindow: 100 },
+    });
+
+    const pageNumbers = screen.getByLabelText(/Page number, of 10000 pages/);
+    expect(pageNumbers).toHaveLength(100 + 1);
+  });
 });