feat(browser): clamp screenshots under 5MB

src/browser/screenshot.test.ts

@@ -0,0 +1,49 @@
+import crypto from "node:crypto";
+
+import sharp from "sharp";
+import { describe, expect, it } from "vitest";
+
+import { normalizeBrowserScreenshot } from "./screenshot.js";
+
+describe("browser screenshot normalization", () => {
+  it("shrinks oversized images to <=2000x2000 and <=5MB", async () => {
+    const width = 2800;
+    const height = 2800;
+    const raw = crypto.randomBytes(width * height * 3);
+    const bigPng = await sharp(raw, { raw: { width, height, channels: 3 } })
+      .png({ compressionLevel: 0 })
+      .toBuffer();
+
+    const normalized = await normalizeBrowserScreenshot(bigPng, {
+      maxSide: 2000,
+      maxBytes: 5 * 1024 * 1024,
+    });
+
+    expect(normalized.buffer.byteLength).toBeLessThanOrEqual(5 * 1024 * 1024);
+    const meta = await sharp(normalized.buffer).metadata();
+    expect(Number(meta.width)).toBeLessThanOrEqual(2000);
+    expect(Number(meta.height)).toBeLessThanOrEqual(2000);
+    expect(normalized.buffer[0]).toBe(0xff);
+    expect(normalized.buffer[1]).toBe(0xd8);
+  }, 20_000);
+
+  it("keeps already-small screenshots unchanged", async () => {
+    const jpeg = await sharp({
+      create: {
+        width: 800,
+        height: 600,
+        channels: 3,
+        background: { r: 255, g: 0, b: 0 },
+      },
+    })
+      .jpeg({ quality: 80 })
+      .toBuffer();
+
+    const normalized = await normalizeBrowserScreenshot(jpeg, {
+      maxSide: 2000,
+      maxBytes: 5 * 1024 * 1024,
+    });
+
+    expect(normalized.buffer.equals(jpeg)).toBe(true);
+  });
+});