refactor(insights): share workbook export and ai defaults

apps/web/src/lib/workbook-export.test.ts

@@ -0,0 +1,53 @@
+import { describe, expect, it } from "vitest";
+import {
+  createWorkbookArrayBuffer,
+  createWorkbookArrayBufferFromSheets,
+} from "./workbook-export.js";
+
+describe("workbook export helpers", () => {
+  it("writes a single-sheet workbook with primitive values", async () => {
+    const buffer = await createWorkbookArrayBuffer("Skills", [
+      ["Skill", "Count", "Active"],
+      ["TypeScript", 4, true],
+      ["Planning", 2, false],
+    ]);
+
+    const ExcelJS = await import("exceljs");
+    const workbook = new ExcelJS.Workbook();
+    await workbook.xlsx.load(Buffer.from(buffer));
+
+    const worksheet = workbook.getWorksheet("Skills");
+    expect(worksheet).toBeDefined();
+    expect(worksheet?.getRow(1).values).toEqual([, "Skill", "Count", "Active"]);
+    expect(worksheet?.getRow(2).values).toEqual([, "TypeScript", 4, true]);
+    expect(worksheet?.getRow(3).values).toEqual([, "Planning", 2, false]);
+  });
+
+  it("writes all provided sheets into the workbook", async () => {
+    const buffer = await createWorkbookArrayBufferFromSheets([
+      {
+        name: "Overview",
+        rows: [["Metric", "Value"], ["Resources", 12]],
+      },
+      {
+        name: "People Finder",
+        rows: [["Name", "Skills"], ["Peter Parker", "Staffing, Forecasting"]],
+      },
+    ]);
+
+    const ExcelJS = await import("exceljs");
+    const workbook = new ExcelJS.Workbook();
+    await workbook.xlsx.load(Buffer.from(buffer));
+
+    expect(workbook.worksheets.map((sheet) => sheet.name)).toEqual([
+      "Overview",
+      "People Finder",
+    ]);
+    expect(workbook.getWorksheet("Overview")?.getRow(2).values).toEqual([, "Resources", 12]);
+    expect(workbook.getWorksheet("People Finder")?.getRow(2).values).toEqual([
+      ,
+      "Peter Parker",
+      "Staffing, Forecasting",
+    ]);
+  });
+});

apps/web/src/lib/workbook-export.ts

@@ -0,0 +1,65 @@
+type ExcelJsModule = typeof import("exceljs");
+
+type WorkbookCellValue = boolean | Date | number | string | null | undefined;
+type WorkbookRow = WorkbookCellValue[];
+type WorkbookSheet = {
+  name: string;
+  rows: WorkbookRow[];
+};
+
+let _excelJs: ExcelJsModule | null = null;
+
+async function getExcelJS() {
+  if (!_excelJs) {
+    _excelJs = await import("exceljs");
+  }
+  return _excelJs;
+}
+
+export async function createWorkbookArrayBuffer(
+  sheetName: string,
+  rows: WorkbookRow[],
+): Promise<ArrayBuffer> {
+  return createWorkbookArrayBufferFromSheets([{ name: sheetName, rows }]);
+}
+
+export async function createWorkbookArrayBufferFromSheets(
+  sheets: WorkbookSheet[],
+): Promise<ArrayBuffer> {
+  const ExcelJS = await getExcelJS();
+  const workbook = new ExcelJS.Workbook();
+
+  for (const sheet of sheets) {
+    const worksheet = workbook.addWorksheet(sheet.name);
+    for (const row of sheet.rows) {
+      worksheet.addRow(row.map((value) => value ?? ""));
+    }
+  }
+
+  const buffer = await workbook.xlsx.writeBuffer();
+  return buffer as ArrayBuffer;
+}
+
+export async function downloadWorkbook(
+  fileName: string,
+  sheetName: string,
+  rows: WorkbookRow[],
+): Promise<void> {
+  return downloadWorkbookSheets(fileName, [{ name: sheetName, rows }]);
+}
+
+export async function downloadWorkbookSheets(
+  fileName: string,
+  sheets: WorkbookSheet[],
+): Promise<void> {
+  const buffer = await createWorkbookArrayBufferFromSheets(sheets);
+  const blob = new Blob([buffer], {
+    type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
+  });
+  const url = URL.createObjectURL(blob);
+  const anchor = document.createElement("a");
+  anchor.href = url;
+  anchor.download = fileName;
+  anchor.click();
+  URL.revokeObjectURL(url);
+}