buffer: improve toJSON() performance

PR-URL: #10895 Reviewed-By: Luigi Pinca <[email protected]> Reviewed-By: Michal Zasso <[email protected]> Reviewed-By: Evan Lucas <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: James M Snell <[email protected]>
nodejs · Mar 9, 2017 · f7879d9 · f7879d9
1 parent 9e6fcbb
commit f7879d9
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Showing 2 changed files with 26 additions and 4 deletions.
diff --git a/benchmark/buffers/buffer-tojson.js b/benchmark/buffers/buffer-tojson.js
@@ -0,0 +1,18 @@
+'use strict';
+
+const common = require('../common.js');
+
+const bench = common.createBenchmark(main, {
+  n: [1e4],
+  len: [0, 10, 256, 4 * 1024]
+});
+
+function main(conf) {
+  var n = +conf.n;
+  var buf = Buffer.allocUnsafe(+conf.len);
+
+  bench.start();
+  for (var i = 0; i < n; ++i)
+    buf.toJSON();
+  bench.end(n);
+}
diff --git a/lib/buffer.js b/lib/buffer.js
@@ -785,10 +785,14 @@ Buffer.prototype.write = function(string, offset, length, encoding) {
 
 
 Buffer.prototype.toJSON = function() {
-  return {
-    type: 'Buffer',
-    data: Array.prototype.slice.call(this, 0)
-  };
+  if (this.length) {
+    const data = [];
+    for (var i = 0; i < this.length; ++i)
+      data[i] = this[i];
+    return { type: 'Buffer', data };
+  } else {
+    return { type: 'Buffer', data: [] };
+  }
 };