buffer: add bufferPool to Buffer.of

Author: gurgunday

benchmark/buffers/buffer-of.js

@@ -0,0 +1,23 @@
+'use strict';
+
+const common = require('../common.js');
+
+// Measure Buffer.of(...items) throughput for various lengths.
+// We prebuild the items array to avoid measuring array construction,
+// and vary the effective iterations with length to keep total work reasonable.
+
+const bench = common.createBenchmark(main, {
+  len: [0, 1, 8, 64, 256, 1024],
+  n: [5e5],
+});
+
+function main({ len, n }) {
+  const items = new Array(len);
+  for (let i = 0; i < len; i++) items[i] = i & 0xFF;
+
+  bench.start();
+  for (let i = 0; i < n; i++) {
+    Buffer.of(...items);
+  }
+  bench.end(n);
+}

lib/buffer.js

@@ -382,10 +382,23 @@ Buffer.copyBytesFrom = function copyBytesFrom(view, offset, length) {
 // Refs: https://tc39.github.io/ecma262/#sec-%typedarray%.of
 // Refs: https://esdiscuss.org/topic/isconstructor#content-11
 const of = (...items) => {
-  const newObj = createUnsafeBuffer(items.length);
-  for (let k = 0; k < items.length; k++)
-    newObj[k] = items[k];
-  return newObj;
+  const len = items.length;
+  if (len === 0) return new FastBuffer();
+  if (len < (Buffer.poolSize >>> 1)) {
+    if (len > (poolSize - poolOffset))
+      createPool();
+    const b = new FastBuffer(allocPool, poolOffset, len);
+    for (let k = 0; k < len; k++)
+      b[k] = items[k];
+    poolOffset += len;
+    alignPool();
+    return b;
+  }
+
+  const b = createUnsafeBuffer(len);
+  for (let k = 0; k < len; k++)
+    b[k] = items[k];
+  return b;
 };
 Buffer.of = of;