1 files changed, 66 insertions, 0 deletions
diff --git a/bench/concat.js b/bench/concat.js
new file mode 100644
index 000000000..46c6e0f7d
--- /dev/null
+++ b/bench/concat.js
@@ -0,0 +1,66 @@
+import { bench, group, run } from "mitata";
+import { readFileSync } from "fs";
+import { allocUnsafe } from "bun";
+
+function polyfill(chunks) {
+  var size = 0;
+  for (const chunk of chunks) {
+    size += chunk.byteLength;
+  }
+  var buffer = new ArrayBuffer(size);
+  var view = new Uint8Array(buffer);
+  var offset = 0;
+  for (const chunk of chunks) {
+    view.set(chunk, offset);
+    offset += chunk.byteLength;
+  }
+  return buffer;
+}
+
+function polyfillUninitialized(chunks) {
+  var size = 0;
+  for (const chunk of chunks) {
+    size += chunk.byteLength;
+  }
+  var view = allocUnsafe(size);
+
+  var offset = 0;
+  for (const chunk of chunks) {
+    view.set(chunk, offset);
+    offset += chunk.byteLength;
+  }
+  return view.buffer;
+}
+
+const chunkGroups = [
+  [Uint8Array.from([123]), Uint8Array.from([456]), Uint8Array.from([789])],
+  Array.from(readFileSync(import.meta.path)).map((a) => Uint8Array.from([a])),
+  [readFileSync(import.meta.path)],
+  Array.from({ length: 42 }, () => readFileSync(import.meta.path)),
+  Array.from({ length: 2 }, () =>
+    new TextEncoder().encode(readFileSync(import.meta.path, "utf8").repeat(100))
+  ),
+];
+
+for (const chunks of chunkGroups) {
+  group(
+    `${chunks.reduce(
+      (prev, curr, i, a) => prev + curr.byteLength,
+      0
+    )} bytes for ${chunks.length} chunks`,
+    () => {
+      bench("Bun.concatArrayBuffers", () => {
+        Bun.concatArrayBuffers(chunks);
+      });
+      bench("Uint8Array.set", () => {
+        polyfill(chunks);
+      });
+
+      bench("Uint8Array.set (uninitialized memory)", () => {
+        polyfillUninitialized(chunks);
+      });
+    }
+  );
+}
+
+await run();