feat: add copyToClipboard() utility with execCommand fallback

apps/web/src/lib/utils.ts

@@ -13,3 +13,24 @@ export function generateId(): string {
   const hex = Array.from(bytes, (b) => b.toString(16).padStart(2, "0")).join("");
   return `${hex.slice(0, 8)}-${hex.slice(8, 12)}-${hex.slice(12, 16)}-${hex.slice(16, 20)}-${hex.slice(20)}`;
 }
+
+export async function copyToClipboard(text: string): Promise<boolean> {
+  try {
+    await navigator.clipboard.writeText(text);
+    return true;
+  } catch {
+    try {
+      const textarea = document.createElement("textarea");
+      textarea.value = text;
+      textarea.style.position = "fixed";
+      textarea.style.opacity = "0";
+      document.body.appendChild(textarea);
+      textarea.select();
+      const ok = document.execCommand("copy");
+      document.body.removeChild(textarea);
+      return ok;
+    } catch {
+      return false;
+    }
+  }
+}

tests/unit/web/utils.test.ts

@@ -1,6 +1,6 @@
 // @vitest-environment jsdom
-import { describe, expect, it } from "vitest";
-import { generateId } from "../../../apps/web/src/lib/utils";
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { copyToClipboard, generateId } from "../../../apps/web/src/lib/utils";
 
 describe("generateId", () => {
   it("returns a valid UUID v4 string", () => {
@@ -13,3 +13,32 @@ describe("generateId", () => {
     expect(ids.size).toBe(100);
   });
 });
+
+describe("copyToClipboard", () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it("returns true when clipboard API succeeds", async () => {
+    Object.assign(navigator, {
+      clipboard: { writeText: vi.fn().mockResolvedValue(undefined) },
+    });
+    expect(await copyToClipboard("hello")).toBe(true);
+    expect(navigator.clipboard.writeText).toHaveBeenCalledWith("hello");
+  });
+
+  it("falls back to execCommand when clipboard API fails", async () => {
+    Object.assign(navigator, { clipboard: undefined });
+    document.execCommand = vi.fn().mockReturnValue(true);
+    expect(await copyToClipboard("hello")).toBe(true);
+    expect(document.execCommand).toHaveBeenCalledWith("copy");
+  });
+
+  it("returns false when both approaches fail", async () => {
+    Object.assign(navigator, { clipboard: undefined });
+    document.execCommand = vi.fn().mockImplementation(() => {
+      throw new Error("not supported");
+    });
+    expect(await copyToClipboard("hello")).toBe(false);
+  });
+});